Tools
MMarquee selection
LLasso selection
PPencil
BBrush
EEraser
GFill bucket
NLine
SSpray can
RRectangle
OOval
TText tool
HGrab/hand (scroll)
Text Tool
ClickPlace text insertion point
TypeEnter characters
EnterNew line
Cmd+EnterCommit text (stay on text tool)
EscapeCancel text
ArrowsMove caret within text
, .Decrease/increase font size
Cmd+ZCharacter-level undo during entry
Selection
Drag insideMove selection
DeleteDelete selected pixels
EscapeDeselect
Polygon Tool
ClickAdd vertex
Near startClose polygon
Double-clickComplete polygon
EscapeCancel polygon
Drawing
/Brush shape selector
YBrush mirrors (symmetry)
IToggle pattern invert
AToggle spray mode (authentic/random)
ShiftConstrain to straight line
Right-clickErase / use background color
XSwap foreground/background
View
1-3Zoom levels (4x, 8x, 16x)
FToggle FatBits mode (8x zoom)
SpaceHold for temporary grab mode
Cmd+ZUndo
Cmd+Shift+ZRedo
Cmd+SSave as PNG (SVG also available)
Reference Image
[ ]Rotate 15° (Shift: 90°)
+ -Scale up/down (or scroll wheel)
DragReposition (when unlocked)
Effects
DDither (Floyd-Steinberg)