[cairo-commit] Branch '1.8' - src/cairo-win32-font.c

[Jeff Muizelaar]

 src/cairo-win32-font.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

New commits:
commit f60da9a379890a3a4cd74cdad48e73c22cb74160
Author: Jeff Muizelaar <jmuizelaar at mozilla.com>
Date:   Thu Dec 18 17:07:25 2008 -0500

    Fix _compute_transform to check for nearly degenerate matrices
    
    If a matrix was something like [0 .000001 0, .000001 0 0] the old code would
    assume that xx and yy were greater than 0 and turn the nearly degenerate matrix
    into an actual degenerate one. This caused things to blow up later on. Now we
    check that our nearly rectangular matrices are not nearly degenerate, and let
    the nearly degenerate ones fall through to the non-rectangular path.
    
    Note: I'm not sure why NEARLY_ZERO(d) is fabs(d) < 1/65536 instead of some
    other value.  Hopefully, it's a useful definition.
    
    This problem was found by a test case attached to:
    https://bugzilla.mozilla.org/show_bug.cgi?id=467423

diff --git a/src/cairo-win32-font.c b/src/cairo-win32-font.c
index 879cfac..b4f125e 100644
--- a/src/cairo-win32-font.c
+++ b/src/cairo-win32-font.c
@@ -158,7 +158,8 @@ _compute_transform (cairo_win32_scaled_font_t *scaled_font,
 {
     cairo_status_t status;
 
-    if (NEARLY_ZERO (sc->yx) && NEARLY_ZERO (sc->xy)) {
+    if (NEARLY_ZERO (sc->yx) && NEARLY_ZERO (sc->xy) &&
+	    !NEARLY_ZERO(sc->xx) && !NEARLY_ZERO(sc->yy)) {
 	scaled_font->preserve_axes = TRUE;
 	scaled_font->x_scale = sc->xx;
 	scaled_font->swap_x = (sc->xx < 0);
@@ -166,7 +167,8 @@ _compute_transform (cairo_win32_scaled_font_t *scaled_font,
 	scaled_font->swap_y = (sc->yy < 0);
 	scaled_font->swap_axes = FALSE;
 
-    } else if (NEARLY_ZERO (sc->xx) && NEARLY_ZERO (sc->yy)) {
+    } else if (NEARLY_ZERO (sc->xx) && NEARLY_ZERO (sc->yy) &&
+	    !NEARLY_ZERO(sc->yx) && !NEARLY_ZERO(sc->xy)) {
 	scaled_font->preserve_axes = TRUE;
 	scaled_font->x_scale = sc->yx;
 	scaled_font->swap_x = (sc->yx < 0);