Bug 694587: Fix pattern repeat calculation

The pattern repeat calculation should be done in pattern space, but
one of the arguments in the calculation was being taken from device
space. Fix this. Also only apply the bias in the case where the
bias would make it larger.

173 progressions.

1 files changed, 9 insertions, 3 deletions

diff --git a/source/fitz/draw-device.c b/source/fitz/draw-device.c
index a92c88b5..355022f3 100644
--- a/source/fitz/draw-device.c
+++ b/source/fitz/draw-device.c
@@ -1857,9 +1857,15 @@ fz_draw_end_tile(fz_device *devp)
 	 * single tile) (see fts_15_1506.pdf for an example). This means that
 	 * we have to bias the left hand/bottom edge calculations by the
 	 * difference between the step and the width/height of the tile. */
-	/* state[0].scissor = view, transformed by ctm */
-	x0 = floorf((area.x0 + xstep - state[0].scissor.x1 + state[0].scissor.x0) / xstep);
-	y0 = floorf((area.y0 + ystep - state[0].scissor.y1 + state[0].scissor.y0) / ystep);
+	/* scissor, xstep and area are all in pattern space. */
+	x0 = xstep - scissor.x1 + scissor.x0;
+	if (x0 > 0)
+		x0 = 0;
+	y0 = ystep - scissor.y1 + scissor.y0;
+	if (y0 > 0)
+		y0 = 0;
+	x0 = floorf((area.x0 + x0) / xstep);
+	y0 = floorf((area.y0 + y0) / ystep);
 	x1 = ceilf(area.x1 / xstep);
 	y1 = ceilf(area.y1 / ystep);