TIEBitmap.MergeAlphaRectTo
Declaration
procedure MergeAlphaRectTo(Dest: TIEBitmap; SrcX, SrcY, DstX, DstY: integer; RectWidth, RectHeight: integer
MergeMethod: TIEMergeMethod = iemMax; MergePercent: Double = 1);
Description
Merges the alpha channel to the
Dest bitmap alpha channel using the specified method.
| Merge Method | Effect |
| iemmMax | Maximum alpha of source and dest is used |
| iemmMin | Minimum alpha of source and dest is used |
| iemmAdd | Alpha of dest is increased by that in source (effect can be reduced by specifying a lower value for MergePercent) |
| iemmSubtract | Alpha of dest is reduced by that in source (effect can be reduced by specifying a lower value for MergePercent) |
| iemmReplaceWithSrc | Replaces alpha of dest, with that of source pixels where alpha > 0 |
Note:
◼Dest must be the same
PixelFormat as the image
◼This method only affects the alpha channel (transparency) of the two images, it does not affect the color channels
TIEBitmap Assignment and Drawing Methods
TIEBitmap Methods
| Method | Mode | Purpose |
| 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 bitmap |
| MergeAlphaRectTo | With TIEBitmap | Merges the alpha channels of two TIEBitmaps 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 |
| Method | Mode | Purpose |
| Assign | From TIEBitmap/TBitmap/TGraphic/TIcon | Copy whole image |
| AssignTo | To TIEBitmap/TBitmap | Copy whole image with optional scaling |
| 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 |
bmp.MergeAlphaRectTo( ImageEnView1.IEBitmap, 0, 0, 0, 0, bmp.Width, bmp.Height, iemmSubtract, 0.50 );
ImageEnView1.IEBitmap.SyncFull();