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st-private: split pixel blurring code out

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The guts are somewhat complicated, and
are potentially reusable for future cairo
fallback code.

https://bugzilla.gnome.org/show_bug.cgi?id=636976
This commit is contained in:
Ray Strode 2011-01-12 19:43:36 -05:00
parent f7ab90b93b
commit 1faee65a68
1 changed files with 62 additions and 43 deletions
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103
src/st/st-private.c
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@ -422,44 +422,31 @@ calculate_gaussian_kernel (gdouble sigma,
return ret;
}
CoglHandle
_st_create_shadow_material (StShadow *shadow_spec,
CoglHandle src_texture)
static guchar *
blur_pixels (guchar *pixels_in,
gint width_in,
gint height_in,
gint rowstride_in,
gdouble blur,
gint *width_out,
gint *height_out,
gint *rowstride_out)
{
static CoglHandle shadow_material_template = COGL_INVALID_HANDLE;
CoglHandle material;
CoglHandle texture;
guchar *pixels_in, *pixels_out;
gint width_in, height_in, rowstride_in;
gint width_out, height_out, rowstride_out;
guchar *pixels_out;
float sigma;
g_return_val_if_fail (shadow_spec != NULL, COGL_INVALID_HANDLE);
g_return_val_if_fail (src_texture != COGL_INVALID_HANDLE,
COGL_INVALID_HANDLE);
/* we use an approximation of the sigma - blur radius relationship used
in Firefox for doing SVG blurs; see
http://mxr.mozilla.org/mozilla-central/source/gfx/thebes/src/gfxBlur.cpp#280
*/
sigma = shadow_spec->blur / 1.9;
sigma = blur / 1.9;
width_in = cogl_texture_get_width (src_texture);
height_in = cogl_texture_get_height (src_texture);
rowstride_in = (width_in + 3) & ~3;
pixels_in = g_malloc0 (rowstride_in * height_in);
cogl_texture_get_data (src_texture, COGL_PIXEL_FORMAT_A_8,
rowstride_in, pixels_in);
if ((guint) shadow_spec->blur == 0)
if ((guint) blur == 0)
{
width_out = width_in;
height_out = height_in;
rowstride_out = rowstride_in;
pixels_out = g_memdup (pixels_in, rowstride_out * height_out);
*width_out = width_in;
*height_out = height_in;
*rowstride_out = rowstride_in;
pixels_out = g_memdup (pixels_in, *rowstride_out * *height_out);
}
else
{
@ -471,18 +458,18 @@ _st_create_shadow_material (StShadow *shadow_spec,
n_values = (gint) 5 * sigma;
half = n_values / 2;
width_out = width_in + 2 * half;
height_out = height_in + 2 * half;
rowstride_out = (width_out + 3) & ~3;
*width_out = width_in + 2 * half;
*height_out = height_in + 2 * half;
*rowstride_out = (*width_out + 3) & ~3;
pixels_out = g_malloc0 (rowstride_out * height_out);
line = g_malloc0 (rowstride_out);
pixels_out = g_malloc0 (*rowstride_out * *height_out);
line = g_malloc0 (*rowstride_out);
kernel = calculate_gaussian_kernel (sigma, n_values);
/* vertical blur */
for (x_in = 0; x_in < width_in; x_in++)
for (y_out = 0; y_out < height_out; y_out++)
for (y_out = 0; y_out < *height_out; y_out++)
{
guchar *pixel_in, *pixel_out;
gint i0, i1;
@ -496,7 +483,7 @@ _st_create_shadow_material (StShadow *shadow_spec,
i1 = MIN (height_in + half - y_in, n_values);
pixel_in = pixels_in + (y_in + i0 - half) * rowstride_in + x_in;
pixel_out = pixels_out + y_out * rowstride_out + (x_in + half);
pixel_out = pixels_out + y_out * *rowstride_out + (x_in + half);
for (i = i0; i < i1; i++)
{
@ -506,11 +493,11 @@ _st_create_shadow_material (StShadow *shadow_spec,
}
/* horizontal blur */
for (y_out = 0; y_out < height_out; y_out++)
for (y_out = 0; y_out < *height_out; y_out++)
{
memcpy (line, pixels_out + y_out * rowstride_out, rowstride_out);
memcpy (line, pixels_out + y_out * *rowstride_out, *rowstride_out);
for (x_out = 0; x_out < width_out; x_out++)
for (x_out = 0; x_out < *width_out; x_out++)
{
gint i0, i1;
guchar *pixel_out, *pixel_in;
@ -519,10 +506,10 @@ _st_create_shadow_material (StShadow *shadow_spec,
* full i range [0, n_values) so that x is in [0, width_out).
*/
i0 = MAX (half - x_out, 0);
i1 = MIN (width_out + half - x_out, n_values);
i1 = MIN (*width_out + half - x_out, n_values);
pixel_in = line + x_out + i0 - half;
pixel_out = pixels_out + rowstride_out * y_out + x_out;
pixel_out = pixels_out + *rowstride_out * y_out + x_out;
*pixel_out = 0;
for (i = i0; i < i1; i++)
@ -536,6 +523,39 @@ _st_create_shadow_material (StShadow *shadow_spec,
g_free (line);
}
return pixels_out;
}
CoglHandle
_st_create_shadow_material (StShadow *shadow_spec,
CoglHandle src_texture)
{
static CoglHandle shadow_material_template = COGL_INVALID_HANDLE;
CoglHandle material;
CoglHandle texture;
guchar *pixels_in, *pixels_out;
gint width_in, height_in, rowstride_in;
gint width_out, height_out, rowstride_out;
g_return_val_if_fail (shadow_spec != NULL, COGL_INVALID_HANDLE);
g_return_val_if_fail (src_texture != COGL_INVALID_HANDLE,
COGL_INVALID_HANDLE);
width_in = cogl_texture_get_width (src_texture);
height_in = cogl_texture_get_height (src_texture);
rowstride_in = (width_in + 3) & ~3;
pixels_in = g_malloc0 (rowstride_in * height_in);
cogl_texture_get_data (src_texture, COGL_PIXEL_FORMAT_A_8,
rowstride_in, pixels_in);
pixels_out = blur_pixels (pixels_in, width_in, height_in, rowstride_in,
shadow_spec->blur,
&width_out, &height_out, &rowstride_out);
g_free (pixels_in);
texture = cogl_texture_new_from_data (width_out,
height_out,
COGL_TEXTURE_NONE,
@ -544,7 +564,6 @@ _st_create_shadow_material (StShadow *shadow_spec,
rowstride_out,
pixels_out);
g_free (pixels_in);
g_free (pixels_out);
if (G_UNLIKELY (shadow_material_template == COGL_INVALID_HANDLE))