MFB: #43073, TrueType bounding box is wrong for angle<>0

Author: Takeshi Abe

ext/gd/libgd/gdft.c

@@ -1108,15 +1108,23 @@ gdImageStringFTEx (gdImage * im, int *brect, int fg, char *fontlist, double ptsi
 		double d1 = sin (angle + 0.78539816339744830962);
 		double d2 = sin (angle - 0.78539816339744830962);
 
+		/* make the center of rotation at (0, 0) */
+		FT_BBox normbox;
+
+		normbox.xMin = 0;
+		normbox.yMin = 0;
+		normbox.xMax = bbox.xMax - bbox.xMin;
+		normbox.yMax = bbox.yMax - bbox.yMin;
+
 		/* rotate bounding rectangle */
-		brect[0] = (int) (bbox.xMin * cos_a - bbox.yMin * sin_a);
-		brect[1] = (int) (bbox.xMin * sin_a + bbox.yMin * cos_a);
-		brect[2] = (int) (bbox.xMax * cos_a - bbox.yMin * sin_a);
-		brect[3] = (int) (bbox.xMax * sin_a + bbox.yMin * cos_a);
-		brect[4] = (int) (bbox.xMax * cos_a - bbox.yMax * sin_a);
-		brect[5] = (int) (bbox.xMax * sin_a + bbox.yMax * cos_a);
-		brect[6] = (int) (bbox.xMin * cos_a - bbox.yMax * sin_a);
-		brect[7] = (int) (bbox.xMin * sin_a + bbox.yMax * cos_a);
+		brect[0] = (int) (normbox.xMin * cos_a - normbox.yMin * sin_a);
+		brect[1] = (int) (normbox.xMin * sin_a + normbox.yMin * cos_a);
+		brect[2] = (int) (normbox.xMax * cos_a - normbox.yMin * sin_a);
+		brect[3] = (int) (normbox.xMax * sin_a + normbox.yMin * cos_a);
+		brect[4] = (int) (normbox.xMax * cos_a - normbox.yMax * sin_a);
+		brect[5] = (int) (normbox.xMax * sin_a + normbox.yMax * cos_a);
+		brect[6] = (int) (normbox.xMin * cos_a - normbox.yMax * sin_a);
+		brect[7] = (int) (normbox.xMin * sin_a + normbox.yMax * cos_a);
 
 		/* scale, round and offset brect */
 		brect[0] = x + gdroundupdown(brect[0], d2 > 0);

ext/gd/tests/bug43073.phpt

@@ -0,0 +1,44 @@
+--TEST--
+Bug #43073 (TrueType bounding box is wrong for angle<>0)
+--SKIPIF--
+<?php
+	if(!extension_loaded('gd')){ die('skip gd extension not available'); }
+?>
+--FILE--
+<?php
+$cwd = dirname(__FILE__);
+$font = "$cwd/test8859.ttf";
+$delta_t = 360.0 / 16; # Make 16 steps around
+$g = imagecreate(800, 800);
+$bgnd  = imagecolorallocate($g, 255, 255, 255);
+$black = imagecolorallocate($g, 0, 0, 0);
+$x = 100;
+$y = 0;
+$cos_t = cos(deg2rad($delta_t));
+$sin_t = sin(deg2rad($delta_t));
+for ($angle = 0.0; $angle < 360.0; $angle += $delta_t) {
+  $bbox = imagettftext($g, 24, $angle, 400+$x, 400+$y, $black, $font, 'ABCDEF');
+  $s = vsprintf("(%d, %d), (%d, %d), (%d, %d), (%d, %d)\n", $bbox);
+  echo $s;
+  $temp = $cos_t * $x + $sin_t * $y;
+  $y    = $cos_t * $y - $sin_t * $x;
+  $x    = $temp;
+}
+?>
+--EXPECTF--
+(500, 400), (579, 400), (579, 370), (500, 370)
+(492, 361), (575, 327), (564, 301), (480, 335)
+(470, 329), (540, 260), (521, 242), (451, 312)
+(438, 307), (478, 210), (461, 204), (420, 301)
+(400, 300), (400, 193), (383, 193), (383, 300)
+(361, 307), (319, 207), (297, 216), (338, 317)
+(329, 329), (254, 254), (233, 275), (307, 351)
+(307, 361), (215, 323), (203, 354), (294, 392)
+(300, 400), (203, 400), (203, 431), (300, 431)
+(307, 438), (219, 474), (229, 501), (318, 465)
+(329, 470), (263, 535), (281, 553), (347, 489)
+(361, 492), (326, 575), (343, 582), (378, 499)
+(400, 500), (400, 584), (416, 584), (416, 500)
+(438, 492), (468, 567), (490, 559), (460, 483)
+(470, 470), (523, 525), (545, 505), (491, 449)
+(492, 438), (560, 467), (572, 436), (504, 408)