draw_sprite_part_ext(sprite, subimg, left, top, width, height, x, y, xscale, yscale, colour, alpha);
|sprite||The index of the sprite to draw.|
|subimg||The subimg (frame) of the sprite to draw (image_index or -1 correlate to the current frame of animation in the object).|
|left||The x position on the sprite of the top left corner of the area to draw.|
|top||The y position on the sprite of the top left corner of the area to draw.|
|width||The width of the area to draw.|
|height||The height of the area to draw.|
|x||The x coordinate of where to draw the sprite.|
|y||The y coordinate of where to draw the sprite.|
|xscale||The horizontal scaling of the sprite, as a multiplier: 1 = normal scaling, 0.5 is half etc...|
|yscale||The vertical scaling of the sprite, as a multiplier: 1 = normal scaling, 0.5 is half etc...|
|colour||The colour with which to blend the sprite. c_white is to display it normally.|
|alpha||The alpha of the sprite (from 0 to 1 where 0 is transparent and 1 opaque).|
This function will draw a part of the chosen sprite at the given position following the same rules as per draw_sprite_part, only now you can scale the part, blend a colour with it, or change its alpha when drawing it to the screen (the same as when drawing a sprite with draw_sprite_ext). You should note that if the texture page permits automatic cropping then this function may not work as expected, since the extra "empty" space around the sprite will have been removed for creating the texture page. To resolve this issue, you will need to set the texture page settings (in the Texture Group Editor) to disable the Automatic Crop.
draw_sprite_part_ext(sprite_index, image_index, 8, 8, sprite_width-16, sprite_height-16, x, y, 2, 0.5, c_black, 1);
This will draw the instances assigned sprite (sprite_index) and its current frame of animation (image_index), however it will shave an 8px margin off all four sides of the sprite. It will then be stretched to double its usual width but half its usual height, and although the alpha is still 1, it will be blended with black (turning it into a silhouette).