The bitmap-stretching mode defines how information is removed from bitmaps that are compressed by using the function.
The BLACKONWHITE (STRETCH_ANDSCANS) and WHITEONBLACK (STRETCH_ORSCANS) modes are typically used to preserve foreground pixels in monochrome bitmaps. The COLORONCOLOR (STRETCH_DELETESCANS) mode is typically used to preserve color in color bitmaps.
The HALFTONE mode requires more processing of the source image than the other three modes; it is slower than the others, but produces higher quality images. Also note that SetBrushOrgEx must be called after setting the HALFTONE mode to avoid brush misalignment.
Additional stretching modes might also be available depending on the capabilities of the device driver.