TCustomBitmap class

In unit Graphics

TCustomBitmap - the base class for TBitmap.

Declaration

pascal

TCustomBitmap = class(TRasterImage)

Inheritance

TCustomBitmap
TRasterImage
TGraphic
TPersistent

Descends from it: TFPImageBitmap

Description

TCustomBitmap is a TRasterImage descendant which implements the base class for TBitmap. It contains image data using the .bmp (Windows bitmap) or .xpm (XPixMap) formats. Image data can be loaded from a file, stream, or resource. The loading routine automatically recognizes the format, and can be used to load images from a Delphi form streams (.dfm files).

When the handle is created, it is up to the widgetset interface (gtk, qt, win32, etc.) to automatically convert it to the best internal format for the platform. That is the reason the Handle is interface dependent. To access the raw image data, see TLazIntfImage in IntfGraphics.pas.

Do not create instances of TCustomBitmap; use the TBitmap descendant.

Properties

`Handle`	public	The operating system Handle associated with this bitmap.
`HandleType`	public	Handle type for the Bitmap.
`Monochrome`	public	True when the image contains monochrome image data.

Methods

`MaskHandleNeeded`	protected	Ensures that a handle is allocated for the image mask (when needed).
`PaletteNeeded`	protected	Ensures that a handle is allocated for the Palette in the image.
`CanShareImage`	protected	Indicates if the image uses the specified shared image class.
`Changed`	protected	Performs actions needed when the image data for the bitmap has been changed.
`CreateDefaultBitmapHandle`	protected	Creates a handle for the bitmap using the bitmap handle type in the bitmap image data.
`FreeMaskHandle`	protected	FreeMaskHandle - method to release Mask handle.
`GetBitmapHandle`	protected	Gets the value for the Handle property.
`GetMaskHandle`	protected	Gets the value for the MaskHandle property.
`GetPalette`	protected	Gets the value for the Palette property.
`GetPixelFormat`	protected	Gets the value for the PixelFormat property.
`GetRawImagePtr`	protected	Gets a pointer with the raw image data.
`GetRawImageDescriptionPtr`	protected	Gets a pointer to the image descriptor for the shared Bitmap image.
`GetSharedImageClass`	protected	Gets the class reference used to create new shared image instances in the class.
`HandleNeeded`	protected	Ensures that the handle for the bitmap has been assigned.
`InternalReleaseBitmapHandle`	protected	InternalReleaseBitmapHandle - releases Bitmap Handle and returns its value.
`InternalReleaseMaskHandle`	protected	InternalReleaseMaskHandle - releases Mask Handle and returns its value.
`InternalReleasePalette`	protected	InternalReleasePalette - releases Palette Handle and returns its value.
`RawimageNeeded`	protected	Ensures that the RawImage data is allocated prior to use.
`SetHandle`	protected	Re-implements the method from the ancestor class.
`SetPixelFormat`	protected	Sets the value for the PixelFormat property.
`UnshareImage`	protected	Frees the shared image in the bitmap, and creates a new one.
`UpdateHandles`	protected	Sets the handles for the image and mask in the shared Bitmap to the specified values.
`Create`	public	Constructor for the class instance.
`Destroy`	public	Destructor for the class instance.
`Assign`	public	Copies values from the specified persistent object into the class instance.
`Clear`	public	Clears the content for the bitmap image.
`FreeImage`	public	Releases the resources for the image when it is discarded.
`LazarusResourceTypeValid`	public	Determines if the specified resource type is valid for the image format.
`BitmapHandleAllocated`	public	Returns True if a handle has been allocated for the Bitmap.
`MaskHandleAllocated`	public	Determines if the mask handle has been allocated for the image.
`PaletteAllocated`	public	Indicates whether a handle has been allocated for a palette in the image.
`ReleaseHandle`	public	Releases the bitmap handle for the shared image.
`SetHandles`	public	Sets handles for the bitmap and the mask to the specified values.
`SetSize`	public	Sets the Height and Width for the image to the specified values.

Inherited

From TRasterImage (50)

ApplyTransparent BeginUpdate BitmapHandle BitmapHandleNeeded Canvas CreateIntfImage Draw EndUpdate FreeSaveStream GetEmpty GetHandle GetHeight GetMasked GetMimeType GetSize GetSupportedSourceMimeTypes GetTransparent GetWidth HandleAllocated LoadFromBitmapHandles LoadFromDevice LoadFromIntfImage LoadFromMimeStream LoadFromRawImage LoadFromStream Mask Masked MaskHandle PixelFormat RawImage ReadData ReadStream ReleaseBitmapHandle ReleaseMaskHandle ReleasePalette RequestTransparentColor SaveStreamNeeded SaveToStream ScanLine SetBitmapHandle SetHeight SetMasked SetMaskHandle SetTransparent SetTransparentMode SetWidth TransparentColor TransparentMode WriteData WriteStream

From TGraphic (27)

DefineProperties Empty Equals GetFileExtensions GetResourceType Height IsStreamFormatSupported LoadFromClipboardFormat LoadFromClipboardFormatID LoadFromFile LoadFromLazarusResource LoadFromResourceID LoadFromResourceName MimeType Modified OnChange OnProgress Palette PaletteModified Progress SaveToClipboardFormat SaveToClipboardFormatID SaveToFile SetModified SetPalette Transparent Width

An experiment, built from Lazarus main 2dfa93c66e of 10-22-2026. Not the official Lazarus documentation.