blendimg!

blendimg!(img1::GMTimage, img2::GMTimage; new=false, transparency=0.5)

Blend the RGB color GMTimage with the shade intensity image (normally obtained with gdaldem). The new argument determines if we return a new RGB image or update the color argument.

Or, blend two 2D UInt8 or 2 RGB images using transparency.

The blending method is the one explained in https://gis.stackexchange.com/questions/255537/merging-hillshade-dem-data-into-color-relief-single-geotiff-with-qgis-and-gdal/255574#255574

• img1, img2: A RGB (GMTimage{UInt8, 3}) or an indexed images (GMTimage{UInt8, 2}). If img1 is RGB and img2 is not, than transparency is ignored. However, if img1 and img2 are of the same type (both RGB or both indexed), that the transparency determines the relative weight of each of them.

• transparency The default value, 0.5, gives equal weight to both images. 0.75 will make img2 weight 3/4 of the total sum, and so forth.

• new If true returns a new GMTimage object, otherwise it changes the img1 content.

Returns nothing if new option has not been used or a GMTimage, either RGB or indexed depending on the options used.