New Stuff

• Acorn now comes with a share extension for 10.10 Yosemite, so you can copy images from Photos to Acorn.

Fixed Stuff

• Fixed a bug where drawing with opacity with the brush tool after clearing a canvas selection wouldn't work properly.
• Fixed a bug where the opacity slider would sometimes be disabled when you turned off visibility for the non active layer.
• Fixed a preview issue with the CIVignette filter.
• Fixed a preview issue with the BC Vignette filter from the BC Image Units package.
• Fixed a redraw issue with the burn tool.
• Fixed a bug where moving to a shape layer's mask would clear the current bitmap selection.
• Fixed a bug where control clicking on a guide didn't always add "Delete Guide" to the contextual menu item (you had to be _right_ on the sucker).
• Fixed a bug where creating a bezier path with mitered joins wouldn't always draw correctly with extreme join angles.
• Fixed a bug where using the boolean operations from the quick config popover wouldn't disable after use (since you would only have a single shape selected at this point, and they wouldn't work).
• Fixed a problem where the ruler wasn't showing the correct origin in the y axis on retina displays.
• If you're running 10.10.3 or later, you'll get to use the very latest non-buggy version of the RAW importer (version 6) if available for your RAW images.

Fixed Stuff

• Fixed a crasher that would sometimes occur when using the eye dropper tool w/ the option key down on a bitmap layer.
• Fixed a problem where some types of RAW images were showing up black in 10.10.
• Fixed a problem where Acorn thumbnails weren't showing up in Finder list views.
• Fixed a crasher when using the instant alpha tool.

Changed Stuff

• Acorn does a better job of managing its memory in the background when batch processing with Automator.
• More visible selection marque when for retina displays.

Fixed Stuff

• Fixed a bug where the selection bounds were not updated when inverting the selection, or extending the selection.
• Fixed a crasher when using the text stroke slider on every other fifth Thursday in even numbered months.

New Stuff

• Acorn will now remove the alpha channel from PNG files if it detects there is no transparency in your image.
• Smart Layer Export now has support for @3x images.

Fixed Stuff

• The pencil tool is a bit more accurate.
• Fixed a bug where merging two layers where the top one had a blend mode of destination out would cause weird clipping.
• Minor speed fix when editing in full screen on 10.10.
• Other minor Yosemite fixes.
• Fixed a bug where the New View window wouldn't update correctly when moving shapes on a canvas with the arrow key.

Minor New Stuff

• New: Command-J will now duplicate the current layer, even if there's no selection (previously this would only work if there was a selection).
• Improvements to text editing in the Do JavaScript Automator action.
• The Merge Visible to New Layer command now works if you only have a single layer.

Fixed Stuff

• Fixed a bug where you could set the blending mode of a layer mask, which makes absolutely no sense whatsoever.
• Fixed a bug where exported PSD files sometimes got the wrong aspect ratio for bitmap layers.
• Fixed a bug where merging multiple shape layers would create a single bitmap layer, instead of the obvious result, which would be a single shape layer.
• Fixed a bug where adding JPEG images to an open image would not open it up in the correct orientation.
• Fixed a crasher when transforming a selection to something very very small. Smaller than the smallest tiny thing you can think of.
• Retina fixes.
• Fixed a bug where duplicating a document would cause weird errors down the road when trying to make new layers.
• Fixed a bug where the New View window would fail to come up if you had certain layer filters applied to your image.
• Fixed a bug where entering .999 into the Levels window wouldn't work correctly.
• Worked around an OS bug where Acorn files of a very large dimension would not save correctly because of corrupt TIFF files being created when LZW compression is involved :| .
• Fixed a bug where the stroke for a new shape would sometimes be reset to 0 when it should have been some other number.
• Fixed a bug where the Rasterize Shape Layers command would only work on the first shape layer you had selected.
• Fixed a bug where inverting a selection would cause boolean selection operations later on to fail.
• Fixed a redraw problem for layers which were pasted in from Keynote.

Experimental Stuff

• New Scripting interface for bitmap layers, which will most likely change in a future major version (hopefully based on feedback):

  var layer = [[[doc baseGroup] layers] objectAtIndex:0];
  
  layer.drawWithHandler(function() {
      var path = [NSBezierPath bezierPathWithOvalInRect:NSMakeRect(0, 0, 100, 100)];
      [[NSColor blackColor] set];
      [path fill];
      // return the area to commit for undo operations
      return NSMakeRect(0, 0, 100, 100);
  });
                  

New Stuff
• New international presets when creating a new image - A3, A4, A5, and A6.
• New Command: Layer ▸ Merge Visible to New Layer (shortcut Command-Option-Shift-E). This will add a new layer, which is a composite of all the visible layers. The menu item for Merge Visible will switch to Merge Visible to New Layer when the Option key is pressed.
• You can now paste an image into the brush designer's canvas, which will then take that image and turn it into a brush.
• New Crop preset: "Document". It adds a crop to the canvas at 90% of the canvas size, and will keep its aspect ratio when resizing.
• New AppleScript command: "add layer mask". Works on either the document or layer object, and if there's a selection on the canvas, that will be used as the mask (otherwise the command will add an empty layer mask). There is also a new Cocoa Script interface to it for the layer object- addMask:.
• When browsing for a new filter in the filters list, changing the front and back colors in the tool palette will now update the colors in the current preview filter.
• The Raw Image Import window now supports full screen editing.
• The gradient tool now has an optional blend mode when used on bitmap layers.
• Acorn will automatically hide palettes when Web Export is used.
• If you paste in dimensions such as "1256x408" into the width field of the new image window, Acorn will recognize that you probably want an image with a height of 408, and will automatically set that value for you.
• The eraser tool now has a precision mode option just like the brush tools do (this will slow down your strokes by 3x, making it easier to add small brush strokes).
• You can now click and drag with the flood fill tool to increase its base tolerance setting, just like with the magic wand and instant alpha tools.
• The tolerance setting for the magic wand will live update when you click and drag on the canvas - which will increase it by the base amount you have set.
• You can now reset individual values in a layer filter by double clicking on its label.
• New shortcut (command-option-shift-n) to create a shape layer.
• Spotlight indexing now includes the fonts in the image as well as the pixel count.
• Pressing the + in the Inspector Palette with the Option and Command keys down will add a new Shape layer (and holding down just the Command key will create a new Group layer, and holding down the option key will duplicate the current layer).
• You can now lock / unlock layers with the command-option-l shortcut.
• Acorn can now open up .pict files. Yes, really. Hello, 1984 called and wants its file format back.
Changed Stuff
• If you have a bitmap layer which is completely transparent, the various transform tools will now let you know that they have no job to do. And if that empty layer has layer filters which generate pixels (such as Render Clouds), Acorn will ask if you want to flatten the filters before continuing.
• The Shape Generator sheet (under Shape ▸ Generate Shapes) will now remember previous settings.
• Acorn no longer lets you set the paragraph spacing of text objects to a negative value. This sometimes worked, even though Acorn was using APIs incorrectly to make it happen- you would get unpredictable results depending on the selected font, and the values were sometimes reset when you reopened a file.
• If the currently selected layer is invisible, the blend mode, opacity slider, and any layer filters it has will now be disabled in the filter palette until the layer is made visible again.
• When using Crop presets that are too big for the canvas, Acorn will now do a better job of scaling things down for you.
• When adding a layer filter preset, Acorn will no longer replace any existing layer filters and instead append to the filters that are already present. If you like the previous behavior, you can hold down the shift key while choosing the preset to replace the current filter(s).
• Web Export: If you have the matte option enabled and are exporting as PNG, Acorn will no longer add a (useless) alpha channel to the image, which will make the file size a bit smaller.
• Deleting the contents of a bitmap layer is way faster now if you've got a huge canvas and just a teeny tiny bit of visible pixels on the layer. Yes, we try and rub the speed on everywhere possible.
• When manipulating star shapes, it will always grow / shrink on either size instead of just one.
• Acorn is taking advantage of more caches to speed up compositing, which helps enormously with layer styles.
• Brought the way background shape layers are selected to be more inline with what happens when selecting bitmap layers. Acorn no longer gives precedence to the currently selected shape layer when clicking on shapes which might be overlapped by other shape layers. If you were enamored with the previous behavior, you can bring it back with this hidden pref: defaults write com.flyingmeat.Acorn4 checkSelectedShapeLayerFirst 1
• Smoother selection animations, as well as rotating colors for the selection (does it stand out more on retina displays now?)
• Less beeping.
• When you have multiple groups selected in the layers list, Acorn will now stuff them into a single group when the New Group command is used. This now matches the same behavior when multiple non-group layers are selected. Previously Acorn would add a new group layer to the selected group (and Acorn will still do this if there is a single group selected).
• Acorn now remembers which color well was selected when you quit and restart.
• New hidden pref for automatically adding a white background when opening a PDF: defaults write com.flyingmeat.Acorn4 whitePDFBackground 1
Fixed Stuff
• Fixed a bug where removing an anchor in the Curves window wouldn't update the preview.
• Fixed a bug where you couldn't properly use the Outline Path command on Line shapes.
• Fixed a crasher when deleting every selected segment of a bezier path.
• Fixed a bug where Web Export wasn't working when in trial mode.
• Fixed a bug where sometimes dragging and dropping an image from the Canvas into the Brush Designer image well (to make a brush shape from the image) wouldn't always work.
• Making selections with the free and polygon selection tools is a bit more natural feeling when zoomed way in.
• Making single pixel selections with the rectangle selection tool is a lot easier to do when zoomed way in (you don't have to drag your cursor around as much).
• Fixed a bug where precision mode with the brush and eraser didn't work great when you were zoomed in our out a bunch.
• The Magic Wand cursor was missing + and - symbols when you held down the shift and option keys to add or subtract to a selection. This has been corrected.
• Fixed a bug where masks in PSD files wouldn't open up correctly with certain images.
• When in Quickmask mode, adding layer filters to the selection works better now.
• The reset button in the filters palette now matches what you get when you add the filter to your layer.
• The tab key now works correctly to move between fields in the Levels window.
• The text insertion point no longer gets layer effects applied to it when you are editing text.
• New document from clipboard now works better when you've got a bunch of shapes copied from a shape layer.
• Fixed a bug where the ungroup layers command wouldn't work correctly for selections of multiple layers.
• When creating shapes, they now snap to rulers and document bounds.
• Fixed a problem where the clone tool didn't give the greatest results when cloning from transparent areas in a layer.
• The File ▸ Add Images… sheet no longer allows you to select images Acorn can't open (such as EPS files).
• Better drawing of text bounds when you're zoomed in and modifying stuff.

New Stuff
• Live font updates to text boxes as you move look through the font list in the text palette.
• Acorn will now give live updates to the blending mode for layers when using the arrow keys on the Blending popup button.
• New preference for a "Super Scrollable Canvas", which basically means you can scroll your canvas around beyond the bounds of your image. This is awesome if you do lots of work with a stylus.
• When making or moving guides, they will now snap to document bounds (if you have the snap options turned on. And did you know you can temporarily disable snapping by holding down the control key? Well, now you do).
• When dropping into Quickmask mode, Acorn will set the front color to white and the back color to black, making it easier to draw in or erase your selection. When you drop out of Quickmask mode, your previous colors are restored.
• If you have multiple layers selected and want to put them in a group, command-g is your friend. And if you have a group layer selected and would like to ungroup it - command-shift-g is also your friend.
• New Clear Selection and Inverse Selection menu items added to the canvas contextual menu when you have a selection.
• If you double click on the Text Palette's baseline, kerning, line height, or paragraph spacing labels, Acorn will reset the value of that slider. If you hold down the command key while double clicking on any of those, Acorn will reset all the text spacing values.
• You can now select non-contiguous layers in the layers list, and merge them into a single layer using the Layer ▸ Merge Layers menu item.
• The contextual menu in the layers list now allows you to merge a clicked layer down.
• Pressing cmd-1 would always scale your canvas to 100%. But new in 4.4: if your canvas is already at 100% and you press cmd-1, the canvas will center itself.
• You can now export an image as a TIFF with CMKY.
• When you change values in the brush designer, updates to your brush strokes are done in the background. This is awesome because it means Acorn stays super responsive when you're making little changes.
• AppleScript stuff:

                  
                  
  tell application "Acorn"
  	tell document 1
  		set current layer to layer 2
  	end tell
  end tell
  
  
  tell application "Acorn"
  	tell document 1
  		
  		tell layer 1
  			load filter preset name "Checkered Brush"
  		end tell
  		
  		# or on the document, which grabs the current layer:
  		# load filter preset name "Checkered Brush"
  		
  	end tell
  	
  end tell
  
                      
                      
                      

Changed Stuff
• You can now have a negative baseline for text shapes.
• Acorn now defaults to keeping objects selected after creating them (though you can change this in the prefs if you liked the old behavior).
• First, some background: Selections are undoable. Shape layers can have selections of their own. Shape layer selections are removed when you switch to another layer. If you are on a shape layer with a selection and move to another layer, your selection would be removed and if you hit undo your selection would come back. However, the active layer was still the one you moved to. So now in version 4.4, if you undo a selection on a shape layer and it's not the active layer, Acorn will now make it active. So an undo (or redo) action could potentially change the active layer. I hope that made sense.
• There was a menu shortcut conflict introduced at some point, where Hide Selection and Hide Layer were both given control-command-h. The shortcut for Hide Layer has been remapped to shift-control-command-h to resolve this.
• If you delete a layer, and then undo it- Acorn will now remember to reselect it if the layer was selected before deletion.
• You can now delete a layer while transforming it, without an alert coming up.
• Crop preset improvements: If you have the option "Keep aspect ratio" enabled when saving a crop preset, and the size of that preset is smaller than the canvas you are using it against, Acorn will scale up the preset to the size of the canvas while preserving the aspect ratio.
• The Automator actions got a little love - please let us know ASAP if something stopped working for you.
• QuickLook previews of Acorn images should be loading faster now. In addition, Acorn now saves thumbnails for native Acorn images, so QuickLook thumbnails now show up super fast for really big images.
• When copying to the clipboard, Acorn will now make sure the dpi for your image tags along as well.
• If a shape layer has a linked mask, and you are moving every shape on the layer, then the mask will move as well. If you don't have all the shapes selected, the layer mask will not move.
Fixed Stuff
• Fixed a bug where Acorn wouldn't open rotated + flipped (as set in the exif orientation information) images correctly.
• Fixed a bug where web export would show text selection if you had… text selected in your canvas.
• Fixed a bug where you couldn't delete a layer with command-delete if it wasn't visible.
• Fixed a bug where option-dragging bitmap layers on the canvas to duplicate them would make them show up in strange places sometimes.
• Fixed a bug where PSD files weren't exported correctly for small layers.
• Fixed a bug where setting the opacity for a layer would sometimes fail if you had just deleted a layer's mask.
• Fixed a bug where switching to a layer mask from a shape layer wouldn't clear the layer selection.
• Fixed a bug where the [ and ] keys wouldn't change the pencil tool brush size.
• Better stylus (Wacom and friends) handling when brushing.
• Fixed a bug with the brush tool where sometimes the first dab with a tablet would show up 100% opaque when it wasn't supposed to.
• Fixed some visual glitches with the Magic Wand HUD.
• Fixed a bug where the ruler bounds markers when moving around a vector shape were drawing in the wrong location on retina displays.
• Fixed a problem where moving your layer around while in Free Rotate would cause it to move at half the speed it should on retina displays.
• Fixed a bug where rotated + squished brushes would sometimes clip when drawing.
• Various canvas free rotate bug fixes.
• Fixed a crasher when using Convert to Bezier shape with rectangles of a certain size (or lack of one actually).
• Fixed a crasher when closing an image when in the middle of a canvas free rotate.
• Fixed a bug where Acorn wouldn't respect the system preferences for max documents to be remembered.
• Fixed a problem where moving selected pixels in a layer mask would cause incorrect drawing.
• The image browser now opens up a bunch more RAW file types.
• Fixed a bug where moving a group layer with snap to document edges turned on would cause real ultimate wrongness.
• Fixed a problem when using the Tilt Shift filter when you were zoomed in.
• Fixed a bug where the name of the layer in the layers list palette would sometimes overlap with the fx button when editing.
Other Stuff
• When entering the versions browser (when Autosave and Versions is turned on in the prefs), Acorn will now hide its tools and inspector palettes.
• defaults write com.flyingmeat.Acorn4 trimToOpaquePixelsOnCopy 1

New Stuff
• New menu item in the View ▸ Guides menu to turn on and off snapping to guides.
• If you have a selection, the frame of the selection will now show up in the status bar of your image's window. This is awesome because sometimes it's hard to know if you have a 1x1 pixel selection or not.
• New option to set the image depth when making a new image.
• The Curves window now has a preview toggle button.
• Crop Presets: There is a new option to resize your image to the original crop dimensions when saving a crop preset.
• Raw Import: The raw import window now includes a histogram for your viewing pleasure.
• Raw Import: You can now choose the color profile you want your image to end up in.
• Raw Import: You can now choose the image depth you want your image to end up in.
• Raw Import: You can now more accurately change the width and height of the image that is being opened.
• Raw Import: New option to adjust noise reduction.
• Raw Import: It's faster!
Changed Stuff
• Web Export more aggressively tries to get your PNGs smaller if your colorspace is sRGB (Acorn will strip out the color profile data in that case).
• BMP files without an embedded colorspace would previously open up in Adobe RGB 1998. In Acorn 4.3, they will now open in whatever your default colorspace is set to (which is sRGB by default). This also matches system behavior.
• Text boxes will now draw an outline when you are rotating or moving them around. This is awesome because it makes it way easier to align stuff up.
• Little pencil and brush improvements with single clicks.
• If it takes more than .2 seconds to render your brush stroke in the Brush Designer, Acorn will cancel the realtime updates for it and wait till you've finished moving your slider around to re-render your stroke with the updated settings.
• When uploading an image to Facebook / Flickr / Wherevr, Acorn will now make sure the exif info for the image tags along.
• Undo should be faster now for Very Large Images.
• If you drag the top colorwell (stroke color) onto a shape, it will now turn on the shape's stroke if it isn't already, and set the stroke color. Likewise, the lower colorwell (fill) will turn on the fill for a shape as well as set it's color.
• The title of the crop preset pulldown will change to the title of the of a selected preset when used.
• The layers list thumbnail drawing has been sped up by a factor of a billion and four.
• The max grid spacing has been bumped up to 500px.
Fixed Stuff
• Fixed a bug where single clicking outside a selection with the selection tool wouldn't clear the selection.
• Fixed a problem where you'd sometimes get transparent edges by using the nearest neighbor scaling option when resizing an image.
• Better handling of mouse position when using the brush tool's precision mode on secondary displays or retina screens.
• Fixed a bug where Flood Fill wasn't working correctly in quick mask mode.
• Fixed some selection redraw problems when your canvas was scaled up to oddball percentages.
• Shadows on shapes now scale correctly when scaling down a bezier shape.
• The gradient palette preview now updates when you undo a gradient change on a selected shape, instead of retaining the previous gradient.
• Fixed a bug where the title of New View windows weren't updated when you saved a document with a new name.
• Fixed a bug where you couldn't use the arrow keys when using the perspective transform to move your image.
• Fixed a redraw problem with the rulers when panning with a trackpad in full screen mode.
• Fixed some cases where you could alter shapes on a locked layer.
• Fixed a pixel grid redraw problem when resizing the canvas.
• Creating a new rect or oval with the option key down will now make it grow in size from the center of the shape (previously you had to press the option key before clicking).
• Fixed an issue where switching from the poly selection tool (without closing a selection you've started) to another tool would cause ferrets to drop from the ceiling.
• Fixed a crasher when using Select All with the crop tool when there was a selection on the canvas already.
• Better shape selection behavior when you've got one of the shape tools selected and you hold down the command key when clicking on a shape to extend your selection.
• Fixed a bug where Acorn would sometimes lose the currently selected layer when re-ordering layers in the layers list..
• Fixed a bug where dragging and dropping a monochrome image from Safari onto Acorn's icon in the Dock would cause the world to implode.
• Fixed a bug where double clicking on the bezier tool in the tools palette to show it's tool menu, and then quickly double clicking on another tool would cause the bezier tool menu to show up again.
• Fixed a bug where text boxes would look funny when editing them and resizing your image at the same time with the option-command window resize widget trick.
• Fixed a bug with PSD export.
• Fixed a bug where next text boxes wouldn't respect certain text palette settings.
• Fixed a bug where you couldn't convert the first anchor point in a bezier path if it wasn't already a curve.
• Fixed a bug when drawing gradients in the quick mask.
• Various little Tilt Shift filter fixes.
• Acorn does a better job of remembering the layers you had selected when you have multiple images open and frequently switch between them.
• The order in which multiple images are dragged from the Finder into the canvas or layers list is now the same (it was backwards in the layers list).
• Fixed a bug where swapping colors in the palette when you had a range of text selected (in a text box) wouldn't change only the selected text.
• Various little fixes with Quartz Composer plugins.
• Fixed a bug where moving selected shapes with the keyboard wouldn't update its position in the inspector palette.
• Fixed a bug where dragging an image from the Finder would sometimes cause it to show up in the wrong location.
• Fixed a bug where resizing the canvas in centimeters didn't work correctly.
• Fixed a bug where pressing the escape key when making a selection with the polygon select tool wouldn't clear out the canvas.
• Fixed a problem when writing out PSD files with interesting layer names.
• Fixed some problems when drawing bezier paths.
• Fixed a bug where CMKY JPEG broke on 10.9.1
• Fixed a bug where Acorn wouldn't ask if you wanted to finish your rotate or transform if you saved your document while in the thick of it.
• Fixed a bug where merging layer groups would sometimes fail to happen with specific layer filters enabled.
• Fixed a bug where swapping the fill and stroke colors on a text box would cause it's text to become selected.
• Other misc. minor fixes.
Other Stuff
• A new hidden pref to enable (or disable) brute force compressing when using PNGs in Web Export. Enabling this will take longer for Acorn to produce your file, but the size might well be smaller.
• A new hidden pref to enable (or disable) preliminary LIFT image support (use File ▸ Export to save your image as a LIFT image).

Changed Stuff
• The magic wand is a bit smarter about selecting transparent pixels.
• If an image has no detectible color profile embedded in it, Acorn will now default to whatever you have set in your preferences for a default color space (by default it's sRGB). Previously it would use the display colorspace on 10.8, and sRGB on 10.9.
• The raw import window now remembers its size between uses.
• Added some better defaults for the tilt shift filter.
• When making a new image from the clipboard, Acorn will now set the DPI based on what's on the clipboard says. For instance, screenshots taken on a retina display and copied to the clipboard will open up with a DPI of 144.
• If you have an image on the clipboard, you can now use the Edit ▸ Paste menu item from the start window to make a new image.
• New option when creating a crop preset to remember the location of the saved crop, or otherwise have it centered in the canvas.
Fixed Stuff
• Fixed a bug that kept you from cropping two documents at once.
• Fixed a bug where resizing the window with the option and command keys down (which will scale your image) wasn't showing the correct preview.
• Fixed a bug where sometimes you couldn't add filters to a newly created layer mask.
• Fixed a problem where you'd sometimes get transparent edges on images when importing a raw image that was scaled down.
• Fixed a bug where bezier lines with no height or width were causing Acorn headaches.
• Fixed a bug where the stepper brush size control in the smudge palette wasn't working.
• Fixed a crash when trying to print an image which has a Japanese file name.
• Fixed a crasher where trying to craftily nest groups inside of themselves would cause Acorn to spin into infinity.
• The grid no longer disappears when you perform a free rotate on the canvas.
• Fixed a redraw problem when moving bitmap layers when zoomed at 75%
• Fixed a bug where some filters on shape layers wouldn't merge down correctly.
• Fixed a scaling bug where pixels near edges would sometimes get stretched out.
• Fixed a bug where an image and window that was greater than 2048 pixels would cause garbage to show up on the canvas (if you had a NVIDIA GeForce GT 120 GPU).
• Fixed a crasher when dragging a specific type of image from Safari onto Acorn's dock icon.

• Fixed a problem where PDF files were not opening correctly.
• Fixed a problem where the New View windows where showing the image in the wrong colorspace.
• Fixed a problem where the New View windows where not properly updating sometimes when moving a bitmap layer.

• Fixed a problem where some images were showing up washed out.
• Fixed a crasher when using the Levels window on certain grayscale images.
• Fixed a crasher when using the Free Rotate command and pressing the "apply" button to commit it from the toll palette.

New Stuff:

• A New "Radial Gradient Blur", which is sort of a like a vignette, but with a blur. It's awesome, try it out.
• You can now change change the depth of an image to 16 bits per component with the Image ▸ Image Depth menu item. Hello deep images!
• RAW files are now opened as 16 bit per component / 64 bit pixel images.
• The default color profile has now been changed to sRGB. (You can also change the default profile in Advanced prefs).
• All drawing is now going directly through OpenGL, which makes things quite a bit faster.
• You can now cycle through a layer's blend modes with Option Shift + or Option Shift - keyboard shortcuts.
• You can now share images with Flickr, Twitter, Facebook, iPhoto, Aperture, and other services using the File ▸ Share menu item.
• The Gaussian Blur filter now has a popup menu item to choose between clamping, blending, or doing nothing when blurring your image.
• The smudge and clone tools no longer share brush sizes with the burn and dodge tools.
• The pencil tool has been revamped with pixel editing in mind, making perfect squares to help you make perfect pixel art.
• You can now set the blend mode for the pencil tool, and in addition to this there's a new "Copy" blend mode for the pencil tool which will replace the brushed pixels with the selected color exactly, instead of blending (which is awesome if you're using a color with alpha in it).
• The eraser tool now has a softness option, which replaces the antialias checkbox.
• The brush slider now grows and shrinks in size at a manageable yet very nice speed when you scrub back and forth.
• The crop palette now has an option to keep the aspect ratio of your crop bounds when saving a new preset.
• Added a new menu item to flatten all layer styles/filters in a document. Open up the Layers menu, hold down the option key, and the "Flatten Layer Filters" menu item changes to "Flatten All Layer Filters".
• The color picker will now pick up alpha correctly if used over an Acorn canvas. The colorspace for the picked color is now calculated correctly as well.
• If you use the arrow keys with a selection (and a selection tool is active) and hold down the option key, Acorn will copy the selection in the direction you press with the keys, thus extending the selection by a pixel (or 10 if you hold down the shift key).
• Minor New Thing: The Levels and Curves now remember their window placement between uses.

Changes:

• Holding down the option key with a bitmap drawing tool while on a shape layer will now pickup a color from the shape layer.
• The Levels filter got some tweaks.
• Bumped up the max font size from 1000 pt to 9999 pt.
• No longer snapping to the guides if they aren't visible.
• Removed the blend mode option for the grid since it slowed things down too much.
• Using the View ▸ Zoom To ▸ Fit in Window menu item while in full screen will now re-center your canvas.

Bug Fixes:

• Fixed a bug where non-contiguous wand selections wouldn't work right if the target color had transparency in it.
• Fix: When resizing the crop bounds by an edge with the shift key down, it'll now keep it's aspect ration (previously this only worked if you used a corner to resize).
• Fixed a bug where changing the default color profile for new images wouldn't take effect until you restarted Acorn.
• Fixed a bug where the Tilt Shift filter wouldn't draw right when you were making a selection.
• Fixed a bug where using the auto levels button in the Levels window would sometimes cause portions of your image to go black for the preview.
• Fixed a bug where the rect selection would clip sometimes if you were zoomed way out on an image.
• Fixed a bug where using the subtract selection mode would not clear the selection if you subtracted the whole selection.
• Fixed a bug where group layer thumbnail previews weren't drawn tall enough in the layers list when you added a mask.
• Fixed a bug where the canvas wouldn't update correctly when moving 1px high shapes with the arrow keys.
• Fixed a bug where a shape stroke could only be set by pressing the enter key in the shape palette.
• Fix: You can now set the opacity of layer masks.
• Fixed a bug with selecting vertical bezier paths with only two anchors.

• App Store only version with sandboxing fixes.

• You can now drag multiple images from the Finder into the canvas or layers list and they will all be added as new layers.
• Change: No longer drawing handles when creating or modifying shape layer graphics.
• Better command-click selection behavior with overlapping shapes on shape layers.
• Added an alert when trying to delete from a bitmap layer when you have a layer filter enabled which is not set to preserver transparency (such as the Render Clouds filter). Otherwise you'd hit delete and nothing would seem to happen.
• Added warnings when trying to use the draw / erase / brush / instant alpha tools on multiple layers at once.
• Tiny speed improvements with Flood Fill (Mr. Paint Bucket), Instant Alpha, and the Magic Wand.
• Better rounding in the window status bar for canvas sizes displaying in centimeters and inches.
• Acorn is a little smarter about sizing the Layer Filters palette when the Window ▸ Gather Palettes menu item is used.
• Fixed a bug with the destination in layer blend mode.
• Filter fixes for Mavericks.
• Fix: Fixed a bug where the corner radius of a shape would get reset.
• Fix: The Quick Config popover wasn't showing up if your cursor wasn't in the canvas. Now it does.
• Fix: The cursor location in the canvas wasn't being updated when making gradients or drawing out shapes. This bug has now been squashed.'
• Fix: When scaling an image with shapes that had gradients on them, the gradients weren't being scaled along. This is now fixed.
• Fix: The freehand selection tool no longer shows a dashed line when making selections on shape layers.
• Fixed a bug where the marching ants selection marker guy wouldn't draw correctly at oddball zoom levels like 57%.
• Fixed a bug where duplicating a layer by dropping it on the + button in the palette wouldn't select it right away. BTW_ you can duplicate a layer by dragging it from the layers list onto the + button in the palette if you didn't know that already.
• Fixed a bug where drawing with the pencil tool and then holding the shift key to draw a straight line from the last point wouldn't work.
• Fixed a bug where using the Bump Distortion Linear filter would cause redraw problems.
• Fixed a the shading of the 1024px version of the Acorn icon.
• Fixed a bug where the shape height field was not updating correctly on Mavericks.
• Fixed a bug where making multiple images in a row would cause the dimensions of the new image window to increase each time if you had the units set to centimeters.
• Fixed a bug where deleting the very first element in a bezier path would sometimes also delete the last one.
• Fixed a bug where sometimes the Web Export preview window wouldn't center images.
• Fixed a bug where the selection bounds in the palette wouldn't update correctly when switching open images.
• Fixed a bug where the background blur filter didn't look correct at zoom levels less than 100%

• New: When exporting an image as JPEG, you can now choose an option to save it as a CMYK image.
• New: You can now flip the canvas vertical or horizontal via the Image ▸ Flip Canvas Horizontal / Vertical menu items.
• New Background Blur filter which will blur the background images behind the current layer, and then mask that blur based on the contents of the current layer. Pro Tip: use white text or boxes to show the blur.
• New: New Mirror filter which will reflect your image in the x and y directions.
• New: Acorn now has a spotlight importer so you can search for acorn images by layer name, text layer contents, width, and height.
• New: When editing a layer name, hitting the tab button will now select the next layer for editing. To end editing, press enter.
• New: You can now change the location and dimensions of a crop with the keyboard. Use the arrow keys to move it around, hold down the option key to change the crop size with the canvas, and hold down the shift key to move or resize in 10 point increments.
• New: Support for multipage TIFF files. If you've got access to a fancy scanner that will place multiple images in a TIFF file, Acorn will now open up each of those pages as a new layer.
• New: If you have multiple layers selected, holding down the command key and clicking on a layer in the canvas will now select the first layer under the mouse click.
• New: If you are viewing your image in shape vector or shape outline only mode, you'll now get a little bit of status text at the bottom of the window letting you know this.
• New: The number of decimal places for the fields in the levels window has been increased for finer control over your adjustments. Plus, it's a forward looking change- we're not always going to be working on only 32 bit images!
• New: When you export an image, Acorn will remember what file type you used last time you exported.
• New: The Shape Quick Config (View ▸ Quick Config Popover) now has alignment options for the selected shapes.
• New: The the Shape Quick Config popover looks a lot better these days.
• New: If you copy a layer's filters to the clipboard and then select multiple layers, you can now paste the copied filters into all the selected layers instead of just the first one.
• New: You can now set the red, blue, or green biases when using the Grayscale filter.
• New: Shape layers now respond to the Layer ▸ Rotate and Transform ▸ Flip Layer Horizontal / Vertical menu items.
• Newish: Exporting as a PDF will try and make a 100% vector PDF if there are no bitmap elements or strange blend modes to get in the way.


• Change: When editing a filter field value, you can now press enter to apply the value. Previously pressing enter would flatten the filter (and now command-enter will flatten the filter).
• Change: After editing a layer name, the canvas now becomes the main window, so cmd-a to select everything (and other shortcuts) will operate on the canvas and not the layers list.
• Change: When you've got one or more layer filters on a bitmap or group layer and you being moving the layer image, any filters with center parameters will be moved along with the layer, keeping the location of the filter in sync with where you originally put it.
• Change: The brush designer is better about interpreting values you put in the various number fields.
• Change: Removed the Image ▸ Invert menu item since it duplicated the Filter ▸ Color Effect ▸ Color Invert filter.
• Change: If you have the move tool active and then select a shape, the palette for that shape will then become active.
• Change: If you have a shape tool selected holding down command and shift at the same time will allow you to select multiple shapes (previously it would only allow a single shape to be selected this way).
• Change: When using the difference boolean operation on selected shapes, contiguous paths will now be broken up into their own independent shapes.
• Change: Previously single clicking with a shape tool on the canvas would cause a shape with some default values to appear. In Acorn 4.1 you now need a double click to do this - single clicking will no longer create a new shape by itself.
• Change: No longer using JavaScript to parse the quick math you can use in pixel text fields, and using NSExpression instead, which is kinda neat.
• Change: Updated to the SQLite 3.7.17, and Acorn now uses memory mapped undo databases (so undo writes are much faster now).
• Change: When pasting shapes from a shape layer that were previously located in an area outside the current canvas, Acorn will now center them in the new canvas.
• Change: Now showing a warning when trying to export a file in the Acorn file format without the .acorn extension.


• Fix: Shape layers now have better hit detection for rotated rects.
• Fixed a bug where nearest neighbor scaling wasn't correctly moving the origin for bitmap layers.
• Fixed a bug where the fuzz stroke filter didn't look correct when viewing your image at less than 100% magnification.
• Fixed a bug where option-dragging a bitmap layer in the canvas would show the wrong size for the preview on retina displays.
• Fixed a bug where shapes would highlight like you could select them if you had multiple layers selected (you couldn't select a shape if you had multiple shapes selected though). However- you can now hold down the command key to select a single layer.
• Fixed a problem where the background of a text box would sometimes flicker in and out when you were editing it.
• Fixed a bug where you could move a locked layer if it was part of a multi-layer selection.
• Fixed a little but where switching to another tool while a crop was in progress (and canceling the crop) would cause the tool not to be selected.
• Fixed a bug where trying to move a layer in the layers list while you were scaling + rotating the layer would cause the operation to fail.
• Fixed a bug where flipping rotated ovals vertically wouldn't work correctly.
• Fixed a bug where double-clicking on the layer filter widget in the layers list causes the layer name to become editable.
• Fixed a bug where using the Add Border to Layer filter wouldn't work correctly if your bitmap layer had a negative origin.
• Fixed a regression where the Edit ▸ Fill window wouldn't work correctly when you had a selection.
• Fixed a bug where Acorn would not complain that you were trying to crop a locked image when you had autosave and versions turned on.
• Fixed a little lag that sometimes occurred when using the brush tool.
• Fixed some redraw issues when moving a control point on a bezier curve.
• Fixed a bug in the web export window where a chevron wasn't showing up on the image format table.
• Fixed a bug where the clone tool wasn't updating the canvas correctly when you were cloning with a selection. Also managed to speed up the clone tool a bit.
• Fix: There was a bug when resizing certain square images in web export would case the aspect ratio to be incorrectly applied.
• Fix: You can now use the undo/redo keyboard shortcuts from the shape quick config popover.
• Fix: The Opacity filter slider now shows as a percentage again, along with the opacity sliders for the Shadow and Inner Shadow filters.
• Fixed a bug where text would sometimes temporarily disappear when cropping.
• Fixed a bug where copying and pasting a bitmap layer with a non-zero frame origin would set reset its origin to zero.
• Completely removed the Acorn 3 filter interface (which was only available thorough a secret keyboard shortcut).

• Fixed a bug where the Save panel would sometimes show a checkbox in the middle of the file listing when you had versions turned on.
• Fixed a bug where the tools palette color well wouldn't update its color if you changed the color of a text box via the font palette.
• Change: When calling a filter via the Filter menu, it is now immediately used for the "Last Filter" menu item instead of waiting for a layer to flatten its filters.
• Fixed a bug where the Grid filter wasn't drawing correctly with some oddball settings.
• Fixed a bug when opening files via JavaScript.
• Fixed some various color mismatch problems with the brush and Edit ▸ Fill command.
• Fixed a problem where the flood fill tool was using a bad color with images which had their colorspace set to device RGB.
• Fixed a problem where temporary undo files weren't being cleaned up.
• Performance improvements when drawing on a retina display, as well as color space fixes on a retina display.
• Making a magic wand selection is a little bit faster now.
• Fixed some memory leaks when using instant alpha or the magic wand tool.
• Fixed an issue where using the Edit ▸ Font ▸ Bigger / Smaller menu item would cause ranges of bold text in a text area to be lost.
• Fixed an issue where free transform would stop keeping the aspect ratio when resizing with the shift key down.
• Fixed a bug where two point bezier shapes would sometimes loose their stroke width when the image was resized.
• Fixed a bug where the selection cursor was showing a little blurry on retina displays.
• Fixed a color space problem when applying Quartz Composer filters to layers.
• Fixed a bug with the JS scripting environment, where calling array.length() wouldn't work correctly.
• Fixed a bug with auto-levels sometimes moving a layer around a bit.
• Fixed a couple of memory leaks.
• Fixed a problem where the fill window wouldn't always do the right thing when filling a layer with the clipboard contents.
• Fixed a problem where changing the matte color in web export would also change the color of any currently selected text boxes.
• Fixed a problem where duplicating a bitmap layer on a RMBP display would sometimes assign the wrong colorspace to the new layer.
• Fixed a slowdown with the brush tool when drawing in a selection.
• Fixed a bug where dragging an image from Safari to Acorn's doc where the img had an href tag to / would cause Acorn to try and find every single image on your computer and stick it in the Image Browser. Which would take a very, very long time.
• Change: Now putting PNG data on the clipboard when using the Copy Merged command, to help out with other apps that don't bother reading the TIFF data.
• Fix: The zoom cursor will now update correctly when trying to zoom to an area, but you toggle the behavior with the option key (to zoom out vs. zoom in).
• Fixed a bug where changing the opacity or blend mode when multiple layers was selected would only work on a single layer.
• Change: PDF files are now opened up as Untitled documents since Acorn won't ever save them in place (export only). This also fixes a bug where Acorn would save over a PDF file on quit.
• Fixed a bug where the shape corner radius would silently reset to 10 when you flipped the corner radius off and back on again without any shapes selected.
• When adding a new shape layer when a group layer is selected, Acorn will now insert that shape layer into the group (which currently happens with bitmap and group layers).
• Fixed a couple of bugs where the ruler wasn't updating correctly when dragging or creating new shapes.
• Fixed a bug where scaling down text would sometimes clip it.
• Single clicking inside of a selection will now remove it (previously this only happened when clicking outside of a selection).
• Fixed an issue where Acorn would remove any extended attributes when saving a file.

• Fixed a bug where applying a filter to a selection wouldn't work when using the menu item and the layer filters window wasn't already up.
• Fixed a bug where the layer thumbnail wasn't showing a moved selection in bitmap layers.
• Layers with the random noise filter added to it now look better when zoomed out.
• Fixed a bug where checking / unchecking the "preserve transparency" option in the random noise filter wouldn't always update the whole canvas.
• Fixed a bug where merging layers while doing a layer transform would cause your transform to be lost, instead of asking if you wanted to apply or commit it.
• The "New Layer from Selection" command will apply layer filters first for the new layer.
• Fixed a problem where you wouldn't get the right cursor while transforming a bitmap layer after rotating a little bit.
• Fixed some bugs with the Brush Designer where you couldn't enter zero for certain brush settings.
• You can now export brushes from the Brush Designer using the File ▸ Export… menu item.
• Fixed a bug where clearing a selection on a bitmap layer when it wasn't the active layer would sometimes cause cut out and moved bits to not be composited to the layer and - well, it's complicated. And now it's fixed.
• Fixed a crasher caused by closing the shape popover window by pressing the escape key and closing the main window later on.
• Certain selection commands will no longer throw up a sheet when working on locked files.
• Fixed a bug when resetting the Grid, Checkerboard, and Pixellate filters would cause the center point to show up in the wrong spot.
• Change: The Pixellate filter no longer clamps the input image to it's edges. The reason Acorn used to do this to stop the natural transparent edges from appearing. The reason why it was taken out was because it created all kinds of funky side effects with the non-destructive nature of the filters. If you're getting transparent edges, change the input center of the filter to a different value, or adjust the scale of the filter to be a whole multiple of the image size.
• Fixed a problem where the sheet was opening too high when saving a preset for the crop tool.
• Fixed some bugs relating to drag + drop from the layers list into the canvas, and option + drag (to make a copy of the current bitmap layer) directly in the canvas.
• Changed the new document tab order so that moving from the width field goes directly to the hight field, and then the unit popup after that.
• Fixed a glitch where moving the canvas from a retina to non retina display would cause the checkerboard background to move a little.
• Fixed a bug where the New View window was scaling incorrect when moving from a regular display to a retina display.
• Change: Window ▸ New View windows are now offset by 20pt from the original image instead of matching the frame exactly.
• Fixed a bug where the checkered background for the Window ▸ New View window wasn't drawing correctly on retina displays.
• Fixed a bug where the About box and Feedback window were stuck behind Acorn's welcome window.
• Fixed a bug where bezier shapes were drawing the wrong bounding boxes.
• Fixed a regression where filters weren't working on layer masks.
• Change: PSD files are now opened up as Untitled documents since Acorn won't ever save them in place (export only) and it also works better with autosave and versions support now.
• Fixed some problems when trying to use selection tools on layer masks that belonged to group and shape layers.
• Fixed a bug where the cursor wouldn't always update correctly when moving in and out of a selection.
• Fixed a bug where the option to turn of antialiasing for shapes wasn't working with the text tool.
• Fixed a bug where Acorn would sometimes restore an empty selection when opening a .acorn file.
• Fixed a bug where making a selection from a layer wouldn't update the selection size in the selection palette.
• Fixed a problem where the layers list would not scroll to the selected layer when you selected a new layer in the canvas.
• Better defaults for shape settings when you launch Acorn for the first time.
• Fixed a crasher that would sporadically happen when you register Acorn.

• Fixed a bug where App Store versions of Acorn wouldn't aways correctly save a .acorn file.
• Updated to the latest Vector Boolean sources which fixes some bugs when unioning shapes (Thanks Andy!).
• Fixed a bug where dragging multiple selected layers from the layers list into another canvas wouldn't copy all the layers.
• Change: When selecting a filter preset, you can now hold down the shift key to have it add to any existing filters on the layer.
• Fixed a bug where choosing a filter preset wouldn't update the display when you had a previous filter selected.
• Change: Acorn will no longer throw up a dialog box when using AppleScript to trim and there's no transparent pixels to trim to.
• Fixed a bug where you couldn't set the color for a selected range in a text box.
• Fixed a bug where the Levels tool wouldn't work correctly with non-rectangular selections.
• Fixed a bug where the Exclude Paths command didn't always work with overlapping shapes.
• Fixed a bug where the levels histogram wasn't showing up correctly on MacBook Airs.
• Fixed a bug where the color and text palettes would incorrectly appear sometimes when pressing the tab key to unhide all the palettes (direct only).

• Fixed a bug where Merlin (the filter HUD) wouldn't always work correctly on first click on the canvas after adding a new filter.
• Fixed a bug where double clicking a text box when you had another shape selected at the same time would cause color changes on all the selected shapes.
• Fixed a bug where RAW import window wouldn't update the image when you typed in values for some of the input fields.

Tools get their own palette now.
It was getting cramped in there, so we broke out the tool icons into their own palette. In addition we updated a bunch of icons and made everything look better in general.

Layer styles and Filters sitting in a tree…
We rolled the layer styles and filters interface into a single non-modal window. This also means that filters are non destructive! You can still chain together filters like before, but now you can undo and redo your adjustments and even save them as part of your Acorn file. In addition to the filter settings being in a non modal window- you can now directly modify filter parameters right on the layer by dragging any little circles that show up when the filter window is present! (And if you'd like the previous filter window back for some reason- we're keeping it around for a little while- just hold down the option and command keys when choosing your filter from the Filters menu.)

The one exception where the filters window isn't modal (and is destructive) is when you are using a filter on a selection.

Curves Adjustments (finally!)
Acorn now has a Curves Adjustment tool, which you can get to from the Image ▸ Curves… menu. To add a new point on a curve, click on the curve and start dragging. To remove a point on a curve, drag it either left or right until it's past the location of the next point on the curve.

Vector tool improvements.

• We went a little crazy and the vector tools have been pretty much re-written. They work faster, there's a new direct anchor selection tool for bezier paths, and more.
• Boolean operations on shapes! Use union, subtract, intersect on selected shapes in a shape layer.
• You can now set the line join style of vector shapes to either, mitered, round, or beveled (using the View ▸ Quick Config Popover on selected shapes).
• You can now turn anti-aliasing on and off for shapes in the Quick Config Popover.
• You can now delete selected segments in a bezier shape by holding down the option key when pressing the delete key.
• Holding down the shift key when changing the control point for a bezier path element will now snap it to 45 degree increments from its home element.
• New Shape ▸ Outline Path menu item, that'll take the stroke of a shape and turn it into a bezier path.
• New Shape ▸ Add Points menu item that you can use on Bezier shapes to add more control points.
• If you have multiple shapes selected and choose Flip Horizontal or Vertical, the flip point will be the center of the all the selected graphics, and not the individual graphics.
• You can now select multiple shapes and rotate them all at once. Hold down the shift key to constrain the rotation to 45° increments.
• You can now select multiple shapes and resize them all at once! Hold down the shift key to keep the aspect ratio.
• New Shape menu to hold all the awesome new shape stuff.
• To select the next point in a bezier shape, press the > key. < will select the previous point. Holding down the shift key will keep the current selected points, and add the next one to the selection.
• New "Draw Shape Pixels/Outlines/Vectors" menu item under the View menu. Instead of stroking and filling all the shapes in the current shape layer, it'll draw the outline only (in outline mode), or scaled vectors (in vector mode), or pixels (which is the normal way tot do things). This can be super useful if you have lots of shapes you're trying to manage and manipulate when zoomed in.
• You can now undo and redo adding segments to a bezier shape. You can also reposition previous anchors while creating it as well.
• When making a new bezier path, you can now hold down the shift key to snap the next line segment to the closest 45° angle.
• The checkbox to turn a shape's stroke on or off has returned from a brief hiatus in Acorn 3.
• You can now use the arrow keys to move selected points in a bezier shape.
• If you're on a shape layer, you can hold down the option + command keys at the same time to copy styles from one shape to all the selected shapes.
• When selecting shapes on a shape layer with the move tool by dragging, shapes will draw their selection bounds as they are selected (or deselected).
• The little sheet that would come up when you made a new shape without dragging it out is now gone, and instead Acorn will insert a rect/oval/arrow/whatever of a reasonable size.
• Pressing delete on a shape layer without anything selected will remove all the shapes in the layer (which is similar to what bitmap layers do as well).
• When creating an oval or a rectangle shape, you can now press the spacebar to reposition the origin of the shape (which is similar to what you can do with canvas selections if you didn't already know that)
• If you have a shape layer copied to the clipboard, using the File ▸ New Image from Clipboard menu item will now make an image with a single shape layer (previously it created a bitmap layer).
• You can now set the size/width of bezier shapes using the shape tool palette.
• When duplicating vector shapes, the copy is now inserted right above the original instead at the very top of the shape layer.
• When adding a new point to a bezier shape, it's now selected so that you can move it with the arrow keys if you like.

Levels tool improvements.
The Levels window got a complete rewrite, with a gamma option (to control mid-tones) as well as an option to update the histogram live.

Speed improvements.
Compositing, filter previews, and everything in general is faster. Way faster Flood Fill, Magic Wand, and Instant Alpha tools. The Render Clouds filter got a little speed bump as well.

Multiple layer selection.
The layers list now allows you to select multiple layers. This means you can re-order, delete, move, or lock a bunch of layers at once.

Other great things worth mentioning.

• Acorn will now remember your selection when you save a file. This is awesome if you have a selection with some filters applied to it- and then quit. Then when you re-open the image, your selection is there, and you can still change the values of the filters to tweak it and such.
• You can now view a layer's mask. Just option click on the mask thumbnail in the layers list, and you will be able to view (and edit) it just like you would any other layer. This is super handy for being able to edit the mask directly.
• You can now export a document or single layer to a new .acorn file.
• Faster Acorn file saves by switching to using TIFF images for the composites (it's twice as fast at compressing than PNG, which was previously used).
• You can now drag and drop images from web browsers into Acorn's start window, and it'll open up a new window for you with the dragged image in it.
• You can now search for filters in the filter sheet picker. THIS IS AWESOME.
• If you've got multiple layers selected, using the move tool in the canvas will now move them all for you.
• Took out the pref to "Change palettes when using keyboard shortcuts" because it was dumb. It's always done now.
• Moving a shape layer with lots of graphics in it is now quite a bit faster.
• Change: When using the new document window, Acorn would look at the image on the clipboard and then autofill the dimensions. This is great, except if you modified those values then went to another app and back while it was up- it would autofill back in the dimensions on the clipboard. So it no longer does this. However- if you liked the old behavior, you can just type ⌘N again, and Acorn will autofill back in the values from the clipboard.
• When copying a layer and then pasting into into an open document, Acorn will also copy along the layer filters and layer mask associated with the image.
• You can now export a group layer as a PDF, and if there are only shape layers in there and on layer styles to be applied- it'll be a pure vector PDF.
• The 'b' and 'n' keys no longer toggle between the brush and pencil tools
• Split the combined Brush + Pencil palette up into their own palettes.
• When moving a shape a shape layer with the shift key down, it will no longer defer to snapping to guides since that can be pretty annoying.
• When changing layer filter values on the canvas, it now has the ability to snap to guides and canvas bounds.
• Hover over filter names and attributes for a tooltip that describes what it's all about.
  
• Removed the Geometry Adjustment filter category, since everything in there is possible using built in tools.
• The file browser window will now give you a warning when you open up a folder and it can't find any images in it.
• When assigning a color profile to your image, you now have an option to change the working color space. This is awesome if you use Acorn for painting! You can set the working color space to "Generic RGB Linear" and the blending of brushes and layers becomes more "painterly" like.
• Faster Acorn file saving by switching to using TIFF images for the composites (TIFF is twice as fast at compressing than PNG, which was previously used).
• New Grid filter which will… add a grid to your canvas. It's handy!
• New Random Noise… filter generator. It's really random.
• You can now drag and drop images from web browsers into Acorn's start window, and it'll open up a new window for you with the dragged image in it.
• Using the selection tools on a shape layer now gets a different look, since it's selecting vectors instead of pixels.
• The Offset and Wrap palette now has some buttons to re-center the image, and also to reset it.
• The Offset filter has been retired in favor of the Layer ▸ Rotate and Transform ▸ Offset and Wrap Layer menu item.
• "Layer Styles" has been renamed to "Layer Filters". Don't let the name change scare you- the new stuff is pretty amazing.
• When moving shapes or layers, you can now hold down the control key to temporarily disable bounds and guide snapping.
• When Acorn is in full screen mode, you can move the canvas anywhere in the screen using the hand tool (quick tip- hold down the space bar and move it around easily). This is handy when you are working on a very large image, and want the lower left corner to be in the middle of your monitor.
• The Edit ▸ Copy Merged menu item now uses the shortcut Control-Command-C (stolen from "Duplicate Shape").
• You'll now get a system notification when a file action script is finished running.
• The image resize sheet now has shortcut keys for selecting the various image resize algorithm (cmd-1, cmd-2, cmd-3)
• The options under the Preset Selections menu now respects the modifier keys when adding to an existing selection (shift=add, option=subtract, shift+option=intersect).
• The file extension is always shown now when exporting an image.
• If you have multiple layers selected and you add a canvas selection, nudging the selection with the move tool will now move that selection across all selected layers.
• New "Open Acorn's App Support Folder" menu item under the Help menu to get to things like custom plugins and saved brushes.
• When resizing your image using the nearest neighbor scaling algorithm, you can now have a width value that's different from a height value.
• Acorn 4 has a new bundle ID! This means that you can keep Acorn 3 around if you'd like, and Acorn 4 won't step on its preferences.
• The Monotone filter does a better job with alpha values now.
• Pressing the ESC key when making a zoom selection will cancel the action.
• Fixed the jaggy zoom box and shape selection box which showed up sometimes when zoomed in.
• You can now change the default grid spacing for a new documents with the following hidden pref:
  defaults write com.flyingmeat.Acorn4 defaultGridSpacing 20
• When moving the canvas between a retina display and a non-retina display, Acorn will adjust the zoom level so that the physical dimensions on the screen don't change.
• The fill window will now remember your last selection between uses (i.e., either fill a color or from the clipboard).
• The file browser window will now give you a warning when you open up a folder and it can't find any images in it.
• No longer setting the default working colorspace for images. Don't worry if you have no idea what this means.
• Acorn is now built with Automatic Reference Counting. I realize you don't care and it probably doesn't even matter in the long run because Apple tends to kill off original technology sooner rather than later, but it was a bit of work and I thought it should be mentioned.
• Command-delete will now delete the selected layers (along with command-control--).

Stuff for Scripters:

• JSTalk scripts no longer need to call autorelease on Cocoa objects.
• New plugin API for scripters: - (CIImage*)renderedCIImage, which grabs a CIImage representation of the layer, with opacity, layer styles, mask, and other such things applied to it.