ImageEn, unit iexBitmaps




procedure StretchRectTo(Dest: TIEBitmap; xDst, yDst, dxDst, dyDst: integer; xSrc, ySrc, dxSrc, dySrc: integer; Filter: TResampleFilter; Transparency: integer = 255; Opacity: double = 1.0);


Stretches source rectangle in destination rectangle.
This method doesn't merge the image with the background, but just replace it (image and alpha).
This function assumes that there is an alpha channel (if not creates it).
Dest must be ie24RGB

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