From Lazarus-ccr

Deutsch (de) English (en) Français (fr)

This page gives an overview of the LCL Carbon interface for Mac OS X and will help new developers.

For installation and creating a first Carbon application refer to Carbon Interface.

Contents 1 Documentation about Carbon 2 Carbon interface development basics 3 What is already working ? 4 What needs to be done next? 5 Bugs 6 Compatibility issues 6.1 Keyboard 6.2 Drawing on canvas outside OnPaint event 6.3 TControl.Color 7 How to add a new control

[edit] Documentation about Carbon

Apple Carbon docs

Carbon Book for download

Carbon Dev

"Learning Carbon" sample book chapter

Free Pascal's Carbon API unit is FPCMacOSAll.pas in /usr/local/share/fpcsrc/packages/extra/univint.

[edit] Carbon interface development basics

• Target Mac OS X version is 10.4
• Avoid using obsolete or deprecated APIs and functions (e. g. QuickDraw vs. Quartz 2D)
• Use object approach
• Check Carbon calls result with OSError function
• Assume UTF-8 encoded strings between LCL and Carbon widgetset (for future Lazarus Unicode support)

[edit] What is already working ?

• Forms and controls - see Roadmap Widgetset dependent components
• Creating TOpenGLControl with AGL context (see components/opengl/)
• Mouse events
• Keyboard events

[edit] What needs to be done next?

Item	Note	Dependencies	Responsible
Mouse Capture releasing
TBrush Patterns	CGPatternCreate
ScreenDC	CGDisplayCapture, CGDisplayGetDrawingContext - CGDisplayCapture locks screen!	TCarbonScreenContext
StretchMaskBlt	Implement: ROP, stretch mode
TCalendar	no counterpart
TFontDialog	FPShowHideFontPanel
TListView	CreateDataBrowserControl
TScrollBox, TCustomControl with scrollbars, TScrollingWinControl	HIScrollViewCreate		Tombo
TClipboard	PasteboardCreate

[edit] Bugs

Item	Note	Dependencies	Responsible
TCustomControl - keyboard focus
TCustomEdit.CharCase	Is ignored when typing text
TMemo.WordWrap	persistent bug, when word wrap is disabled the memo doesn't scroll to caret
TMaskEdit	Every typed char is doubled

[edit] Compatibility issues

[edit] Keyboard

• Apple Command key is mapped to ssCtrl per Apple Guidelines
• Apple control key is mapped to ssMeta
• Apple option key is mapped to its inscription, i.e. ssAlt
• Virtual key codes mapping (depends on keyboard language layout!)
• Shortcuts indication (ampersand)

[edit] Drawing on canvas outside OnPaint event

• paints into QuickDraw window port, maybe QDBeginCGContext, QDEndCGContext would help

Note that Quickdraw is deprecated as of Mac OS X 10.5, so in the long term this needs another solution.

[edit] TControl.Color

• background of Carbon controls is transparent

[edit] How to add a new control

For example TButton.

TButton is defined in lcl/buttons.pp. This is the platform independent part of the LCL, which is used by the normal LCL programmer.

Its widgetset class is in lcl/widgetset/wsbuttons.pp. This is the platform independent base for all widgetsets (carbon, gtk, win32, ...).

Its Carbon interface class is in lcl/interfaces/carbon/carbonwsbuttons.pp:

 TCarbonWSButton = class(TWSButton)
 private
 protected
 public
   class function  CreateHandle(const AWinControl: TWinControl; const AParams: TCreateParams): TLCLIntfHandle; override;
 end;

Every WS class that actually implements something must be registered. See the initialization section at the end of the carbonwsXXX.pp unit:

 RegisterWSComponent(TCustomButton, TCarbonWSButton);

TCarbonWSButton overrides CreateHandle to create a Carbon button helper class called TCarbonButton in carbonprivate.pp, which really creates the button control in the Carbon and installs event handlers.