Merge branch 'clamp-coordinates' into 'master'

Clamp path coordinates

Closes poppler/poppler#1250

See merge request cairo/cairo!325

.gitlab-ci/ignore-pdf-argb32.txt

@@ -13,6 +13,8 @@ ft-show-glyphs-positioning
 ft-text-vertical-layout-type1
 ft-text-vertical-layout-type3
 halo-transform
+huge-linear
+huge-radial
 linear-gradient-reflect
 mask
 overlapping-glyphs

.gitlab-ci/ignore-pdf-rgb24.txt

@@ -23,6 +23,8 @@ ft-text-vertical-layout-type3
 gradient-zero-stops
 gradient-zero-stops-mask
 halo-transform
+huge-linear
+huge-radial
 image-surface-source
 linear-gradient-one-stop
 linear-gradient-reflect

src/cairo-default-context.c

@@ -713,10 +713,12 @@ _cairo_default_context_move_to (void *abstract_cr, double x, double y)
 {
     cairo_default_context_t *cr = abstract_cr;
     cairo_fixed_t x_fixed, y_fixed;
+    double width;
 
     _cairo_gstate_user_to_backend (cr->gstate, &x, &y);
-    x_fixed = _cairo_fixed_from_double (x);
-    y_fixed = _cairo_fixed_from_double (y);
+    width = _cairo_gstate_get_line_width (cr->gstate);
+    x_fixed = _cairo_fixed_from_double_clamped (x, width);
+    y_fixed = _cairo_fixed_from_double_clamped (y, width);
 
     return _cairo_path_fixed_move_to (cr->path, x_fixed, y_fixed);
 }
@@ -726,10 +728,12 @@ _cairo_default_context_line_to (void *abstract_cr, double x, double y)
 {
     cairo_default_context_t *cr = abstract_cr;
     cairo_fixed_t x_fixed, y_fixed;
+    double width;
 
     _cairo_gstate_user_to_backend (cr->gstate, &x, &y);
-    x_fixed = _cairo_fixed_from_double (x);
-    y_fixed = _cairo_fixed_from_double (y);
+    width = _cairo_gstate_get_line_width (cr->gstate);
+    x_fixed = _cairo_fixed_from_double_clamped (x, width);
+    y_fixed = _cairo_fixed_from_double_clamped (y, width);
 
     return _cairo_path_fixed_line_to (cr->path, x_fixed, y_fixed);
 }
@@ -744,19 +748,21 @@ _cairo_default_context_curve_to (void *abstract_cr,
     cairo_fixed_t x1_fixed, y1_fixed;
     cairo_fixed_t x2_fixed, y2_fixed;
     cairo_fixed_t x3_fixed, y3_fixed;
+    double width;
 
     _cairo_gstate_user_to_backend (cr->gstate, &x1, &y1);
     _cairo_gstate_user_to_backend (cr->gstate, &x2, &y2);
     _cairo_gstate_user_to_backend (cr->gstate, &x3, &y3);
+    width = _cairo_gstate_get_line_width (cr->gstate);
 
-    x1_fixed = _cairo_fixed_from_double (x1);
-    y1_fixed = _cairo_fixed_from_double (y1);
+    x1_fixed = _cairo_fixed_from_double_clamped (x1, width);
+    y1_fixed = _cairo_fixed_from_double_clamped (y1, width);
 
-    x2_fixed = _cairo_fixed_from_double (x2);
-    y2_fixed = _cairo_fixed_from_double (y2);
+    x2_fixed = _cairo_fixed_from_double_clamped (x2, width);
+    y2_fixed = _cairo_fixed_from_double_clamped (y2, width);
 
-    x3_fixed = _cairo_fixed_from_double (x3);
-    y3_fixed = _cairo_fixed_from_double (y3);
+    x3_fixed = _cairo_fixed_from_double_clamped (x3, width);
+    y3_fixed = _cairo_fixed_from_double_clamped (y3, width);
 
     return _cairo_path_fixed_curve_to (cr->path,
 				       x1_fixed, y1_fixed,

src/cairo-fixed-private.h

@@ -53,6 +53,11 @@
 #define CAIRO_FIXED_ONE_DOUBLE ((double)(1 << CAIRO_FIXED_FRAC_BITS))
 #define CAIRO_FIXED_EPSILON    ((cairo_fixed_t)(1))
 
+#define CAIRO_FIXED_MAX        INT32_MAX /* Maximum fixed point value */
+#define CAIRO_FIXED_MIN        INT32_MIN /* Minimum fixed point value */
+#define CAIRO_FIXED_MAX_DOUBLE (((double) CAIRO_FIXED_MAX) / CAIRO_FIXED_ONE_DOUBLE)
+#define CAIRO_FIXED_MIN_DOUBLE (((double) CAIRO_FIXED_MIN) / CAIRO_FIXED_ONE_DOUBLE)
+
 #define CAIRO_FIXED_ERROR_DOUBLE (1. / (2 * CAIRO_FIXED_ONE_DOUBLE))
 
 #define CAIRO_FIXED_FRAC_MASK  ((cairo_fixed_t)(((cairo_fixed_unsigned_t)(-1)) >> (CAIRO_FIXED_BITS - CAIRO_FIXED_FRAC_BITS)))
@@ -128,6 +133,17 @@ _cairo_fixed_from_double (double d)
 # error See cairo-fixed-private.h for details.
 #endif
 
+static inline cairo_fixed_t
+_cairo_fixed_from_double_clamped (double d, double tolerance)
+{
+    if (d > CAIRO_FIXED_MAX_DOUBLE - tolerance)
+       d = CAIRO_FIXED_MAX_DOUBLE - tolerance;
+    else if (d < CAIRO_FIXED_MIN_DOUBLE + tolerance)
+       d = CAIRO_FIXED_MIN_DOUBLE + tolerance;
+
+    return _cairo_fixed_from_double (d);
+}
+
 static inline cairo_fixed_t
 _cairo_fixed_from_26_6 (uint32_t i)
 {

test/long-lines.c

@@ -29,6 +29,9 @@
 #define LINE_WIDTH	1.
 #define SIZE		10
 #define LINE_NBR	6
+#define WIDTH (SIZE * (LINE_NBR + 1))
+#define HEIGHT (SIZE * (LINE_NBR + 1))
+
 
 struct {
     double length;
@@ -66,8 +69,8 @@ draw (cairo_t *cr, int width, int height)
     }
 
     /* This should display a perfect vertically centered black line */
-    cairo_move_to (cr, 0.5, -1e100);
-    cairo_line_to (cr, pos,  1e100);
+    cairo_move_to (cr, -1e100, HEIGHT/2);
+    cairo_line_to (cr, 1e100, HEIGHT/2);
     cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
     cairo_stroke (cr);
 
@@ -80,6 +83,6 @@ CAIRO_TEST (long_lines,
 	    "\nLong lines are not drawn due to the limitations of the internal 16.16 fixed-point coordinates",
 	    "stroke, stress", /* keywords */
 	    NULL, /* requirements */
-	    SIZE * (LINE_NBR + 1), SIZE * (LINE_NBR + 1),
+	    WIDTH, HEIGHT,
 	    NULL, draw)