Attachment 15692 Details for Bug 15349 – Patch tightning bounds in some cases

[patch] Patch tightning bounds in some cases

pixel-exact-pattern-bounds.patch (text/plain), 2.78 KB, created by Owen Taylor on 2008-04-04 20:57:10 UTC

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Creator: Owen Taylor

Created: 2008-04-04 20:57:10 UTC

Size: 2.78 KB

patch

obsolete

>commit 8509bb51a947f6e966228fe8879000be5461e29c
>Author: Owen W. Taylor <otaylor@fishsoup.net>
>Date:   Fri Apr 4 23:45:19 2008 -0400
>
>    Make pattern bounds tighter for pixel-exact transformations
>    cairo-matrix.c cairoint.: Add _cairo_matrix_is_pixel_exact
>    cairo-pattern.c: Treat pixel-exact transformations like
>      they were always FILTER_NEAREST
>
>diff --git a/src/cairo-matrix.c b/src/cairo-matrix.c
>index d10d156..7262d90 100644
>--- a/src/cairo-matrix.c
>+++ b/src/cairo-matrix.c
>@@ -600,6 +600,36 @@ _cairo_matrix_is_integer_translation (const cairo_matrix_t *matrix,
>     return FALSE;
> }
> 
>+/* By pixel exact here, we mean a matrix that is composed only of
>+ * 90 degree rotations, flips, and and integer translations. If
>+ * we transform an image with a pixel-exact matrix, filtering
>+ * is not useful.
>+ */
>+cairo_private cairo_bool_t
>+_cairo_matrix_is_pixel_exact(const cairo_matrix_t *matrix)
>+{
>+    cairo_fixed_t x0_fixed, y0_fixed;
>+
>+    if (matrix->xy == 0.0 && matrix->yx == 0.0) {
>+	if (!(matrix->xx == 1.0 || matrix->xx == -1.0))
>+	    return FALSE;
>+	if (!(matrix->yy == 1.0 || matrix->yy == -1.0))
>+	    return FALSE;
>+    } else if (matrix->xx == 0.0 && matrix->yy == 0.0) {
>+	if (!(matrix->xy == 1.0 || matrix->xy == -1.0))
>+	    return FALSE;
>+	if (!(matrix->yx == 1.0 || matrix->yx == -1.0))
>+	    return FALSE;
>+    } else {
>+	return FALSE;
>+    }
>+    
>+    x0_fixed = _cairo_fixed_from_double (matrix->x0);
>+    y0_fixed = _cairo_fixed_from_double (matrix->y0);
>+    
>+    return _cairo_fixed_is_integer (x0_fixed) && _cairo_fixed_is_integer (y0_fixed);
>+}
>+				     
> /*
>   A circle in user space is transformed into an ellipse in device space.
> 
>diff --git a/src/cairo-pattern.c b/src/cairo-pattern.c
>index e1d4b5c..6aed729 100644
>--- a/src/cairo-pattern.c
>+++ b/src/cairo-pattern.c
>@@ -2000,10 +2000,15 @@ _cairo_pattern_get_extents (cairo_pattern_t         *pattern,
> 	case CAIRO_FILTER_GOOD:
> 	case CAIRO_FILTER_BEST:
> 	case CAIRO_FILTER_BILINEAR:
>-	    x1 -= 0.5;
>-	    y1 -= 0.5;
>-	    x2 += 0.5;
>-	    y2 += 0.5;
>+	    /* We assume that the backend will not blur out the image
>+	     * when a pixel-for-pixel copy is possible.
>+	     */
>+	    if (!_cairo_matrix_is_pixel_exact(&imatrix)) {
>+		x1 -= 0.5;
>+		y1 -= 0.5;
>+		x2 += 0.5;
>+		y2 += 0.5;
>+	    }
> 	    break;
> 	case CAIRO_FILTER_FAST:
> 	case CAIRO_FILTER_NEAREST:
>diff --git a/src/cairoint.h b/src/cairoint.h
>index 01ad567..768e6b3 100644
>--- a/src/cairoint.h
>+++ b/src/cairoint.h
>@@ -2051,6 +2051,9 @@ cairo_private cairo_bool_t
> _cairo_matrix_is_integer_translation(const cairo_matrix_t *matrix,
> 				     int *itx, int *ity);
> 
>+cairo_private cairo_bool_t
>+_cairo_matrix_is_pixel_exact(const cairo_matrix_t *matrix);
>+				     
> cairo_private double
> _cairo_matrix_transformed_circle_major_axis(cairo_matrix_t *matrix, double radius);
>

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Attachments on bug 15349: 15673 | 15674 | 15692 | 15740 | 15742

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