Add edge data types

diff --git a/pixman/pixman-private.h b/pixman/pixman-private.h
index 85a670f..0d5125e 100644 (file)
--- a/pixman/pixman-private.h
+++ b/pixman/pixman-private.h
@@ -648,4 +648,53 @@ void pixmanCompositeRect (const FbComposeData *data,
            (out_stride) * (y) + (mul) * (x);                           \
     } while (0)
 
+
+/*
+ * Edges
+ */
+
+#define MAX_ALPHA(n)   ((1 << (n)) - 1)
+#define N_Y_FRAC(n)    ((n) == 1 ? 1 : (1 << ((n)/2)) - 1)
+#define N_X_FRAC(n)    ((1 << ((n)/2)) + 1)
+
+#define STEP_Y_SMALL(n)        (xFixed1 / N_Y_FRAC(n))
+#define STEP_Y_BIG(n)  (xFixed1 - (N_Y_FRAC(n) - 1) * STEP_Y_SMALL(n))
+
+#define Y_FRAC_FIRST(n)        (STEP_Y_SMALL(n) / 2)
+#define Y_FRAC_LAST(n) (Y_FRAC_FIRST(n) + (N_Y_FRAC(n) - 1) * STEP_Y_SMALL(n))
+
+#define STEP_X_SMALL(n)        (xFixed1 / N_X_FRAC(n))
+#define STEP_X_BIG(n)  (xFixed1 - (N_X_FRAC(n) - 1) * STEP_X_SMALL(n))
+
+#define X_FRAC_FIRST(n)        (STEP_X_SMALL(n) / 2)
+#define X_FRAC_LAST(n) (X_FRAC_FIRST(n) + (N_X_FRAC(n) - 1) * STEP_X_SMALL(n))
+
+#define RenderSamplesX(x,n)    ((n) == 1 ? 0 : (xFixedFrac (x) + X_FRAC_FIRST(n)) / STEP_X_SMALL(n))
+
+/*
+ * Step across a small sample grid gap
+ */
+#define RenderEdgeStepSmall(edge) { \
+    edge->x += edge->stepx_small;   \
+    edge->e += edge->dx_small;     \
+    if (edge->e > 0)               \
+    {                              \
+       edge->e -= edge->dy;        \
+       edge->x += edge->signdx;    \
+    }                              \
+}
+
+/*
+ * Step across a large sample grid gap
+ */
+#define RenderEdgeStepBig(edge) {   \
+    edge->x += edge->stepx_big;            \
+    edge->e += edge->dx_big;       \
+    if (edge->e > 0)               \
+    {                              \
+       edge->e -= edge->dy;        \
+       edge->x += edge->signdx;    \
+    }                              \
+}
+
 #endif /* PIXMAN_PRIVATE_H */

diff --git a/pixman/pixman.h b/pixman/pixman.h
index 3110c36..3550f69 100644 (file)
--- a/pixman/pixman.h
+++ b/pixman/pixman.h
@@ -44,7 +44,7 @@ SOFTWARE.
 
 ******************************************************************/
 /*
- * Copyright © 1998 Keith Packard
+ * Copyright © 1998, 2004 Keith Packard
  * Copyright   2007 Red Hat, Inc.
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
@@ -290,6 +290,52 @@ pixman_bool_t              pixman_region_selfcheck (pixman_region16_t *region);
 void                   pixman_region_reset(pixman_region16_t *region, pixman_box16_t *box);
 
 /*
+ * Trapezoids
+ */
+typedef struct pixman_edge pixman_edge_t;
+
+/*
+ * An edge structure.  This represents a single polygon edge
+ * and can be quickly stepped across small or large gaps in the
+ * sample grid
+ */
+struct pixman_render_edge
+{
+    pixman_fixed_t     x;
+    pixman_fixed_t     e;
+    pixman_fixed_t   stepx;
+    pixman_fixed_t   signdx;
+    pixman_fixed_t   dy;
+    pixman_fixed_t   dx;
+
+    pixman_fixed_t   stepx_small;
+    pixman_fixed_t   stepx_big;
+    pixman_fixed_t   dx_small;
+    pixman_fixed_t   dx_big;
+};
+
+pixman_fixed_t pixman_sample_ceil_y        (pixman_fixed_t       y,
+                                           int                  bpp);
+pixman_fixed_t pixman_sample_floor_y       (pixman_fixed_t       y,
+                                           int                  bpp);
+void           pixman_edge_step            (pixman_edge_t       *e,
+                                           int                  n);
+void           pixman_edge_init            (pixman_edge_t       *e,
+                                           int                  bpp,
+                                           pixman_fixed_t       y_start,
+                                           pixman_fixed_t       x_top,
+                                           pixman_fixed_t       y_top,
+                                           pixman_fixed_t       x_bot,
+                                           pixman_fixed_t       y_bot);
+void           pixman_line_fixed_edge_init (pixman_edge_t       *e,
+                                           int                  bpp,
+                                           pixman_fixed_t       y,
+                                           pixman_line_fixed_t *line,
+                                           int                  x_off,
+                                           int                  y_off);
+
+
+/*
  * Images
  */
 typedef  union pixman_image            pixman_image_t;