[Bf-blender-cvs] SVN commit: /data/svn/bf-blender [46227] trunk/blender/source/blender/ editors/interface/interface_draw.c: Fix #31266: Track preview is shifted by half a pixel

[Sergey Sharybin]

Revision: 46227
          http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=46227
Author:   nazgul
Date:     2012-05-03 10:40:04 +0000 (Thu, 03 May 2012)
Log Message:
-----------
Fix #31266: Track preview is shifted by half a pixel

Modified Paths:
--------------
    trunk/blender/source/blender/editors/interface/interface_draw.c

Modified: trunk/blender/source/blender/editors/interface/interface_draw.c
===================================================================
--- trunk/blender/source/blender/editors/interface/interface_draw.c	2012-05-03 10:14:08 UTC (rev 46226)
+++ trunk/blender/source/blender/editors/interface/interface_draw.c	2012-05-03 10:40:04 UTC (rev 46227)
@@ -1469,8 +1469,11 @@
 	ImBuf *scaleibuf;
 	const float scalex = ((float)ibuf->x - 2 * margin) / width;
 	const float scaley = ((float)ibuf->y - 2 * margin) / height;
-	float off_x = (int)track_pos[0] - track_pos[0] + 0.5f;
-	float off_y = (int)track_pos[1] - track_pos[1] + 0.5f;
+	/* NOTE: 1.0f = 0.5f for integer coordinate coorrection (center of pixel vs. left bottom corner of bixel)
+	 *       and 0.5f for centering image in preview (cross is draving at exact center of widget so image
+	 *       should be shifted by half of pixel for correct centering) - sergey */
+	float off_x = (int)track_pos[0] - track_pos[0] + 1.0f;
+	float off_y = (int)track_pos[1] - track_pos[1] + 1.0f;
 	int x, y;
 
 	scaleibuf = IMB_allocImBuf(width, height, 32, IB_rect);