Carbon interface internals/de

From Free Pascal wiki
Revision as of 12:18, 22 February 2008 by Swen (talk | contribs)
Jump to navigationJump to search

Deutsch (de) English (en)

macOSlogo.png

Dieser Artikel behandelt ausschließlich macOS.

Siehe auch: Multiplatform Programming Guide/de

Apple iOS new.svg

Dieser Artikel behandelt ausschließlich iOS.

Siehe auch: Multiplatform Programming Guide/de


Diese Seite bietet einen Überblick über die LCL Carbon Schnittstelle für Mac OS X und soll neuen Entwicklern helfen.

Für die Installation und Erzeugung einer ersten Carbon Anwendung lesen sie zunächst Carbon Interface.

Dokumentation über Carbon

Die Carbon API unit von FreePascal ist FPCMacOSAll.pas in /usr/local/share/fpcsrc/packages/extra/univint.

Other Interfaces

Platform specific Tips

Interface Development Articles

Carbon Schnittstelle Entwicklungs-Grundlagen

  • Die Mac OS X Zielversion ist 10.4
  • Vermeiden sie die Verwendung von veralteten oder ausgemusterten APIs und Funktionen (z.B. QuickDraw vs. Quartz 2D)
  • Verwenden sie den Objektansatz
  • Prüfen sie die Ergebnisse von Carbon Aufrufen mit der OSError Funktion
  • erwenden Sie UTF-8 kodierte Zeichenketten zwischen LCL und dem Carbon widgetset (für zukünftige Lazarus Unicode Unterstützung)

Was funktioniert bereits ?

Working components in the Carbon interface

Was muss als nächstes getan werden ?

Siehe Bug Tracker Carbon open issues

Carbon IDE Bugs

Item Anmerkung Abhängigkeiten Verantwortlich
'...' buttons in dialogs Now they are too large I think
OK/Cancel Many dialogs have non-Mac check-X glyphs
Menu bar Too wide for 1024x768 display resolution
Lazarus menu Help About and app prefs (Environment options) should be accessible here
Menus Many missing or non-standard menu shortcuts:

File New should be Cmd+N
File Save As should be Shift+Cmd+S
File Quit should be Cmd+Q
Search Find should be Cmd+F
Search Find Next should be Cmd+G
Search Find Previous should be Shift+Cmd+G
(Goto line and Procedure List need to be reassigned)
Option+Cmd+F does not bring up Search Results
F11 behaves weird!

Siehe Bug Tracker Carbon IDE open issues

Implementation Details

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 is not reliable (depends on keyboard language layout!)

Application

  • Title: You cannot change it at runtime. You have to set it in Application Bundle.
  • OnDropFiles event is fired when file is dropped on application dock icon or opened via Finder if is associated. You have to enable this event in Application Bundle.

Drawing and measuring text precisely in parts

If you want to draw (via TextOut, TextRect) or measure (via TextWidth, TextHeight) text divided into various parts and rely it will be displayed same each time not depending on its division, you have to disable some default typographic features (like kerning, fractional positioning, ...) of Canvas. You can choose one of the following:

  • CarbonWidgetSet.SetTextFractional(Canvas, False); // from CarbonInt unit
  • TCarbonCustomControl(CustomControl.Handle).TextFractional := False; // from CarbonPrivate unit
  • TCarbonDeviceContext(Canvas.Handle)..TextFractional := False; // from CarbonCanvas unit

Screenshot taking

The only possible efficient way of taking a screenshot on Mac OS X is using OpenGL. Apple provides a demonstration function which returns a CGImageRef with the screenshot. This function was converted to Pascal and is available on the glgrab.pas unit on the carbon interface directory. This function requires the Apple-specific parts of the Apple OpenGL headers, and those didn't exist yet in Pascal at this point, so the headers were translated and are placed on opengl.pas until they are released on a stable Free Pascal.

It isn't possible to directly access the bytes of a CGImageRef, and the Screenshot taking rountine (TWidgetset.RawImage_fromDevice) requires doing that, so the image needs to be drawn to a CGContextRef which uses a memory area allocated by us as buffer. This painting has the great advantage of converting from the internal format of the screenshot bytes to the very convenient ARGB, 32-bits depth, 8-bits per channel format that is default to LCL.

Kompatibilitätsprobleme

These are things that will probably never be solved.

Mouse.CursorPos changing does not generate mouse (move) events

Release mouse capture is not supported

Command line parameters

Because Carbon applications are executed via Application Bundle, command line parameters are not passed. You have to use OnDropFiles event to detect openning associated files.

Shortcuts indication is not supported

Drawing on Canvas outside OnPaint event is not supported

Drawing on screen device context is not supported

TCustomControl.Color of clBtnFace makes its background transparent

TWinControl.Font fsStrikeOut is not supported

TForm

  • Icon is not supported
  • ShowInTaskbar is not supported

TEdit.PasswordChar different then default is not supported

TMemo.WordWrap when is disabled, does not allow to scroll text horizontally

TListBox.Columns is not supported

TComboBox

  • OnDropDown is called when set focus
  • OnCloseUp is called when released focus
  • DroppedDown does not show drop down list when style is csDropDownList
  • DropDownCount is not supported
  • Style: csSimple, csOwnerDrawFixed and csOwnerDrawVariable are not supported

TPanel.Bevelxxx: bvLowered and bvSpace are not supported

TBitBtn.Spacing is not supported

TTrackBar

  • LineSize is not supported
  • ScalePos is not supported
  • TickMarks are not supported

TProgressBar

  • BarShowText is not supported
  • Smooth is not supported
  • Step is not supported

TColorDialog.Title is not supported

Wie man ein neues Bedienelement hinzufügt

Zum Beispiel TButton.

TButton wird definiert in lcl/buttons.pp. Dies ist der plattformunabhängige Teil der LCL, welcher vom normalen LCL Programmierer benutzt wird.

Seine widgetset Klasse befindet sich in lcl/widgetset/wsbuttons.pp. Dies ist die plattformabhängige Basis für alle widgetsets (carbon, gtk, win32, ...).

Seine Carbon Schnittstellenklasse ist in lcl/interfaces/carbon/carbonwsbuttons.pp:

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

Jede WS Klasse, die tatsächlich etwas implementiert, muss registriert werden. Schauen sie sich den initialization Abschnitt am Ende der carbonwsXXX.pp Unit an:

 RegisterWSComponent(TCustomButton, TCarbonWSButton);

TCarbonWSButton setzt CreateHandle außer Kraft und erzeugt eine Carbon-Schaltfläche-Helfer-Klasse namens TCarbonButton in carbonprivate.pp, die die Schaltfläche in Carbon erzeugt und die Event-Handler installiert.