pipewire: Properly pass sizes to gs_draw_sprite_subregion

The gs_draw_sprite_subregion() function is used when a cropping
rectangle is received from PipeWire. It is usually used by
compositors to implement window screencast - where a large and
mostly empty frame is sent, the window contents are only a small
part of it, and the crop rectangle tells us that.

Recently the wlroots implementation of portals started to use it
to implement cropping, and it exposed a bug in the PipeWire code
in OBS Studio. The gs_draw_sprite_subregion() function takes a
pair of floats representing position (x, y) and a pair of floats
representing size (width, height). The PipeWire code, however,
passes a second pair of positions (x2, y2) instead of sizes, and
it causes overrendering the crop area.

This bug wasn't hit yet because both GNOME and KDE implementations
always send (0, 0) as position, which practically never trigger
this condition.

Pass only width and height to gs_draw_sprite_subregion(), instead
of summing them with x and y.

Fixes obsproject#4982

plugins/linux-capture/pipewire.c

@@ -1200,9 +1200,8 @@ void obs_pipewire_video_render(obs_pipewire_data *obs_pw, gs_effect_t *effect)
 
 	if (has_effective_crop(obs_pw)) {
 		gs_draw_sprite_subregion(obs_pw->texture, 0, obs_pw->crop.x,
-					 obs_pw->crop.y,
-					 obs_pw->crop.x + obs_pw->crop.width,
-					 obs_pw->crop.y + obs_pw->crop.height);
+					 obs_pw->crop.y, obs_pw->crop.width,
+					 obs_pw->crop.height);
 	} else {
 		gs_draw_sprite(obs_pw->texture, 0, 0, 0);
 	}