TIEBitmap.MergeWithAlpha

Declaration

procedure MergeWithAlpha(Bitmap: TIEBitmap; DstX: integer=0; DstY: integer=0; DstWidth: integer=-1; DstHeight: integer=-1; Transparency: integer=255; ResampleFilter: TResampleFilter = rfNone; Operation: TIERenderOperation = ielNormal; Resample: boolean = false; SrcX: integer = 0; SrcY: integer = 0; Opacity: double = 1.0);

Description

Merges pixels and alpha channel of Bitmap (source) with the background.
The Bitmap PixelFormat must be ie24RGB or ie32RGB.

Parameter	Description
Bitmap	Source image with alpha channel to merge with the background
DstX	Horizontal destination position
DstY	Vertical destination position
DstWidth	Destination width (Bitmap will be resampled/cropped to this value). -1 = the same width of source bitmap
DstHeight	Destination height (Bitmap will be resampled/cropped to this value). -1 = the same height of source bitmap
Transparency	Transparency of source bitmap. 0 = fully transparent, 255 = fully opaque
ResampleFilter	Interpolation filter used when source bitmap needs to be resampled
Operation	Blender operation to perform
Resample	If true Bitmap is resampled, otherwise it is cropped
SrcX	Source bitmap left position
SrcY	Source bitmap top position

Opacity vs Transparency

Both the Opacity and Transparency parameters provide the same functionality. Transparency is the traditional ImageEn value, whereas Opacity provides easier PSD compatibility.
While they can be used in combination, generally only one will be used, i.e. leave Opacity=1 and make use of transparency, or alternatively, leave Transparency=255 and make use of Opacity. For example, for 50% opacity: Transparency = 255 and Opacity = 0.5, or Transparency = 128 and Opacity = 1.0

TIEBitmap Assignment and Drawing Methods

TIEBitmap Methods

Method	Mode	Notes
Assign	From TIEBitmap/TBitmap/TGraphic/TIcon	Copy whole image
AssignImage	From TIEBitmap	Like assign, but does not copy the alpha channel
AssignRect	From TIEBitmap/TBitmap	Copy a specified rect
CopyAndConvertFormat	From TIEBitmap	Copy whole image
CopyRectTo	To TIEBitmap	Copy rect to another image (without scaling)
CopyWithMask1	To TIEBitmap	Copy image using a mask to specify what is copied from the source
CopyWithMask2	To TIEBitmap	Copy image using a mask to specify what is replaced in the destintation
DrawToTIEBitmap	To TIEBitmap	Copies all or part of the image to a specified position and/or size
JoinBitmaps	From two TIEBitmaps	Draws two bitmaps to a single bitmaps
MergeAlphaRectTo	With TIEBitmap	Merges all or part of two TIEBitmaps with alpha channels to a specified position using merge rules
MergeWithAlpha	With TIEBitmap	Merges all or part of two TIEBitmaps with alpha channels to a specified position
RenderToTIEBitmapEx	To TIEBitmap	Extended drawing of content to a TIEBitmap
StretchRectTo	To TIEBitmap	Copy rect to dest rect in another image (with scaling)
SwitchTo	To TIEBitmap	Move content from one TIEBitmap to another

TBitmap Methods

Method	Mode	Notes
Assign	From TIEBitmap/TBitmap/TGraphic/TIcon	Copy whole image
AssignRect	From TIEBitmap/TBitmap	Copy a specified rect
CopyFromTBitmap	From TBitmap	Copy whole image
CopyToTBitmap	To TBitmap	Copy whole image
RenderToTBitmapEx	To TBitmap	Extended drawing of content to a TBitmap

TCanvas Methods

Method	Mode	Notes
DrawToCanvas	To TCanvas	Copies whole image to canvas at specified position (ignoring the alpha channel)
DrawToCanvasWithAlpha	To TCanvas	Copies whole image to canvas at specified position (honoring the alpha channel)
RenderToCanvas	To TCanvas	Extended drawing of content to a TCanvas (ignoring the alpha channel)
RenderToCanvasWithAlpha	To TCanvas	Extended drawing of content to a TCanvas (honoring the alpha channel)

Example

// Merge uplayer.png over background.png
ImageEnView1.IO.LoadFromFile('background.png');
ImageEnView2.IO.LoadFromFile('uplayer.png');
ImageEnView1.IEBitmap.MergeWithAlpha(ImageEnView2.IEBitmap);
ImageEnView1.Update;
ImageEnView1.IO.SaveToFile('output.png');

TIEBitmap.MergeWithAlpha