Attachment 107344 Details for Bug 84396 – increase coverage area precision

[patch] increase coverage area precision

0001-EXTRA_Y.patch (text/plain), 4.83 KB, created by Massimo on 2014-10-05 07:39:01 UTC

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Creator: Massimo

Created: 2014-10-05 07:39:01 UTC

Size: 4.83 KB

patch

obsolete

>From f6fee91130f0cff49e334d7191b7a49bcd7d8afd Mon Sep 17 00:00:00 2001
>From: Massimo Valentini <mvalentini@src.gnome.org>
>Date: Sun, 5 Oct 2014 09:24:53 +0200
>Subject: [PATCH] EXTRA_Y
>
>---
> src/cairo-tor-scan-converter.c | 42 ++++++++++++++++++++++--------------------
> 1 file changed, 22 insertions(+), 20 deletions(-)
>
>diff --git a/src/cairo-tor-scan-converter.c b/src/cairo-tor-scan-converter.c
>index 4adcafb..21d639e 100644
>--- a/src/cairo-tor-scan-converter.c
>+++ b/src/cairo-tor-scan-converter.c
>@@ -117,6 +117,7 @@ typedef cairo_status_t glitter_status_t;
> #define GLITTER_INPUT_BITS CAIRO_FIXED_FRAC_BITS
> #define GRID_X_BITS CAIRO_FIXED_FRAC_BITS
> #define GRID_Y 15
>+#define EXTRA_Y 17
> 
> /* Set glitter up to use a cairo span renderer to do the coverage
>  * blitting. */
>@@ -237,7 +238,7 @@ typedef int grid_scaled_y_t;
>  * vertices are given in grid scaled coordinates.  The scale factor
>  * comes from needing to accurately represent the area 0.5*dx*dy of a
>  * triangle with base dx and height dy in grid scaled numbers. */
>-#define GRID_XY (2*GRID_X*GRID_Y) /* Unit area on the grid. */
>+#define GRID_XY (2*GRID_X*GRID_Y*EXTRA_Y) /* Unit area on the grid. */
> 
> /* GRID_AREA_TO_ALPHA(area): map [0,GRID_XY] to [0,255]. */
> #if GRID_XY == 510
>@@ -404,8 +405,8 @@ struct polygon {
> struct cell {
>     struct cell		*next;
>     int			 x;
>-    int16_t		 uncovered_area;
>-    int16_t		 covered_height;
>+    int32_t		 uncovered_area;
>+    int32_t		 covered_height;
> };
> 
> /* A cell list represents the scan line sparsely as cells ordered by
>@@ -649,7 +650,8 @@ cell_list_alloc (struct cell_list *cells,
>     cell->next = tail->next;
>     tail->next = cell;
>     cell->x = x;
>-    *(uint32_t *)&cell->uncovered_area = 0;
>+    cell->uncovered_area = 0;
>+    cell->covered_height = 0;
> 
>     return cell;
> }
>@@ -737,13 +739,13 @@ cell_list_add_subspan(struct cell_list *cells,
>     if (ix1 != ix2) {
> 	struct cell_pair p;
> 	p = cell_list_find_pair(cells, ix1, ix2);
>-	p.cell1->uncovered_area += 2*fx1;
>-	++p.cell1->covered_height;
>-	p.cell2->uncovered_area -= 2*fx2;
>-	--p.cell2->covered_height;
>+	p.cell1->uncovered_area += 2*fx1 * EXTRA_Y;
>+	p.cell1->covered_height += EXTRA_Y;
>+	p.cell2->uncovered_area -= 2*fx2 * EXTRA_Y;
>+	p.cell2->covered_height -= EXTRA_Y;
>     } else {
> 	struct cell *cell = cell_list_find(cells, ix1);
>-	cell->uncovered_area += 2*(fx1-fx2);
>+	cell->uncovered_area += 2*(fx1-fx2) * EXTRA_Y;
>     }
> }
> 
>@@ -829,8 +831,8 @@ cell_list_render_edge(struct cell_list *cells,
> 	/* We always know that ix1 is >= the cell list cursor in this
> 	 * case due to the no-intersections precondition.  */
> 	struct cell *cell = cell_list_find(cells, ix1);
>-	cell->covered_height += sign*GRID_Y;
>-	cell->uncovered_area += sign*(fx1 + fx2)*GRID_Y;
>+	cell->covered_height += sign*GRID_Y * EXTRA_Y;
>+	cell->uncovered_area += sign*(fx1 + fx2)*GRID_Y * EXTRA_Y;
> 	return;
>     }
> 
>@@ -864,7 +866,7 @@ cell_list_render_edge(struct cell_list *cells,
> 
> 	tmp = (ix1 + 1) * GRID_X * edge->dy;
> 	tmp -= x1.quo * edge->dy + x1.rem;
>-	tmp *= GRID_Y;
>+	tmp *= GRID_Y * EXTRA_Y;
> 
> 	y.quo = tmp / dx;
> 	y.rem = tmp % dx;
>@@ -894,8 +896,8 @@ cell_list_render_edge(struct cell_list *cells,
> 	    struct cell *cell = pair.cell2;
> 	    struct quorem dydx_full;
> 
>-	    dydx_full.quo = GRID_Y * GRID_X * edge->dy / dx;
>-	    dydx_full.rem = GRID_Y * GRID_X * edge->dy % dx;
>+	    dydx_full.quo = EXTRA_Y * GRID_Y * GRID_X * edge->dy / dx;
>+	    dydx_full.rem = EXTRA_Y * GRID_Y * GRID_X * edge->dy % dx;
> 
> 	    ++ix1;
> 	    do {
>@@ -916,8 +918,8 @@ cell_list_render_edge(struct cell_list *cells,
> 
> 	    pair.cell2 = cell;
> 	}
>-	pair.cell2->uncovered_area += sign*(GRID_Y - y_last)*fx2;
>-	pair.cell2->covered_height += sign*(GRID_Y - y_last);
>+	pair.cell2->uncovered_area += sign*(EXTRA_Y * GRID_Y - y_last)*fx2;
>+	pair.cell2->covered_height += sign*(EXTRA_Y * GRID_Y - y_last);
>     }
> }
> 
>@@ -1576,7 +1578,7 @@ blit_a8 (struct cell_list *cells,
> {
>     struct cell *cell = cells->head.next;
>     int prev_x = xmin, last_x = -1;
>-    int16_t cover = 0, last_cover = 0;
>+    int32_t cover = 0, last_cover = 0;
>     unsigned num_spans;
> 
>     if (cell == &cells->tail)
>@@ -1593,7 +1595,7 @@ blit_a8 (struct cell_list *cells,
>     num_spans = 0;
>     for (; cell->x < xmax; cell = cell->next) {
> 	int x = cell->x;
>-	int16_t area;
>+	int32_t area;
> 
> 	if (x > prev_x && cover != last_cover) {
> 	    spans[num_spans].x = prev_x;
>@@ -1645,7 +1647,7 @@ blit_a1 (struct cell_list *cells,
> {
>     struct cell *cell = cells->head.next;
>     int prev_x = xmin, last_x = -1;
>-    int16_t cover = 0;
>+    int32_t cover = 0;
>     uint8_t coverage, last_cover = 0;
>     unsigned num_spans;
> 
>@@ -1663,7 +1665,7 @@ blit_a1 (struct cell_list *cells,
>     num_spans = 0;
>     for (; cell->x < xmax; cell = cell->next) {
> 	int x = cell->x;
>-	int16_t area;
>+	int32_t area;
> 
> 	coverage = GRID_AREA_TO_A1 (cover);
> 	if (x > prev_x && coverage != last_cover) {
>-- 
>1.9.3
>

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Attachments on bug 84396: 106961 | 106989 | 107095 | 107101 | 107103 | 107104 | 107186 | 107189 | 107344

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