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Speed up drawing of the grid.

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Přemysl Eric Janouch 2011-02-10 06:03:41 +01:00
parent 39fb4bb56f
commit d96acedcdb
1 changed files with 41 additions and 18 deletions
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59
liblogdiag/ld-canvas.c
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@ -216,6 +216,7 @@ static gdouble ld_canvas_get_scale_in_px (LdCanvas *self);
static void ld_canvas_color_set (LdCanvasColor *color,
gdouble r, gdouble g, gdouble b, gdouble a);
static void ld_canvas_color_apply (LdCanvasColor *color, cairo_t *cr);
static guint32 ld_canvas_color_to_cairo_argb (LdCanvasColor *color);
static gdouble point_to_line_segment_distance
(const LdPoint *point, const LdPoint *p1, const LdPoint *p2);
@ -997,6 +998,15 @@ ld_canvas_color_apply (LdCanvasColor *color, cairo_t *cr)
cairo_set_source_rgba (cr, color->r, color->g, color->b, color->a);
}
static guint32
ld_canvas_color_to_cairo_argb (LdCanvasColor *color)
{
return (guint) (color->a * 255) << 24
| (guint) (color->r * color->a * 255) << 16
| (guint) (color->g * color->a * 255) << 8
| (guint) (color->b * color->a * 255);
}
static gdouble
point_to_line_segment_distance
(const LdPoint *point, const LdPoint *p1, const LdPoint *p2)
@ -1998,7 +2008,10 @@ draw_grid (GtkWidget *widget, DrawData *data)
gint grid_factor;
gdouble x_init, y_init;
gdouble x, y;
gdouble x_round, y_round;
cairo_surface_t *grid_surface;
gint stride;
unsigned char *pixels;
guint32 color;
grid_step = data->scale;
grid_factor = 1;
@ -2008,9 +2021,13 @@ draw_grid (GtkWidget *widget, DrawData *data)
grid_factor *= 5;
}
ld_canvas_color_apply (COLOR_GET (data->self, COLOR_GRID), data->cr);
cairo_set_line_width (data->cr, 1);
cairo_set_line_cap (data->cr, CAIRO_LINE_CAP_ROUND);
/* Paint manually on our own raster surface for speed. */
stride = cairo_format_stride_for_width
(CAIRO_FORMAT_ARGB32, data->exposed_rect.width);
pixels = g_malloc0 (stride * data->exposed_rect.height);
grid_surface = cairo_image_surface_create_for_data
(pixels, CAIRO_FORMAT_ARGB32,
data->exposed_rect.width, data->exposed_rect.height, stride);
/* Get coordinates of the top-left point. */
ld_canvas_widget_to_diagram_coords (data->self,
@ -2024,20 +2041,26 @@ draw_grid (GtkWidget *widget, DrawData *data)
ld_canvas_diagram_to_widget_coords (data->self,
x_init, y_init, &x_init, &y_init);
/* Iterate over all the points. */
for (x = x_init; x <= data->exposed_rect.x + data->exposed_rect.width;
x += grid_step)
{
for (y = y_init; y <= data->exposed_rect.y + data->exposed_rect.height;
y += grid_step)
{
x_round = floor (x) + 0.5;
y_round = floor (y) + 0.5;
cairo_move_to (data->cr, x_round, y_round);
cairo_line_to (data->cr, x_round, y_round);
}
}
cairo_stroke (data->cr);
x_init -= data->exposed_rect.x;
y_init -= data->exposed_rect.y;
while (x_init < 0)
x_init += grid_step;
while (y_init < 0)
y_init += grid_step;
color = ld_canvas_color_to_cairo_argb (COLOR_GET (data->self, COLOR_GRID));
for (x = x_init; x < data->exposed_rect.width; x += grid_step)
for (y = y_init; y < data->exposed_rect.height; y += grid_step)
*((guint32 *) (pixels + stride * (gint) y) + (gint) x) = color;
cairo_set_source_surface (data->cr, grid_surface,
data->exposed_rect.x, data->exposed_rect.y);
cairo_paint (data->cr);
cairo_surface_destroy (grid_surface);
g_free (pixels);
}
static void