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blur-effect: Use sigma value instead of blur radius

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Almost all implementations, including CSS [1] of gaussian blurs use the
sigma/standard deviation value as the input parameter, even if they call
that value "radius". Since using sigma is more correct mathematically
and avoids confusion for people used to other blur implementations, use
that parameter here, too.

[1] https://www.w3.org/TR/filter-effects-1/#funcdef-filter-blur

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/991
This commit is contained in:
Jonas Dreßler 2020-02-10 15:34:57 +01:00 committed by Georges Basile Stavracas Neto
parent d26bb38be9
commit f351cfa2f7
3 changed files with 43 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
js/ui/unlockDialog.js
View File

@ -19,7 +19,7 @@ const SCREENSAVER_SCHEMA = 'org.gnome.desktop.screensaver';
const CROSSFADE_TIME = 300;
const BLUR_BRIGHTNESS = 0.55;
const BLUR_RADIUS = 200;
const BLUR_SIGMA = 60;
const SUMMARY_ICON_SIZE = 32;
@ -516,7 +516,7 @@ var UnlockDialog = GObject.registerClass({
widget.add_effect(new Shell.BlurEffect({
brightness: BLUR_BRIGHTNESS,
blur_radius: BLUR_RADIUS,
sigma: BLUR_SIGMA,
}));
}

77
src/shell-blur-effect.c
View File

@ -80,16 +80,13 @@
*/
static const gchar *gaussian_blur_glsl_declarations =
"uniform float blur_radius; \n"
"uniform float sigma; \n"
"uniform float pixel_step; \n"
"uniform int vertical; \n";
static const gchar *gaussian_blur_glsl =
" int horizontal = 1 - vertical; \n"
" \n"
" int n_steps = int (ceil (blur_radius)); \n"
" float sigma = float (n_steps) / 3.0; \n"
" \n"
" vec2 uv = vec2 (cogl_tex_coord.st); \n"
" \n"
" vec3 gauss_coefficient; \n"
@ -102,6 +99,8 @@ static const gchar *gaussian_blur_glsl =
" vec4 ret = texture2D (cogl_sampler, uv) * gauss_coefficient.x; \n"
" gauss_coefficient.xy *= gauss_coefficient.yz; \n"
" \n"
" int n_steps = int (ceil (3 * sigma)); \n"
" \n"
" for (int i = 1; i < n_steps; i += 2) { \n"
" float coefficient_subtotal = gauss_coefficient.x; \n"
" gauss_coefficient.xy *= gauss_coefficient.yz; \n"
@ -129,7 +128,7 @@ static const gchar *brightness_glsl =
" cogl_color_out.rgb *= brightness; \n";
#define MIN_DOWNSCALE_SIZE 256.f
#define MAX_BLUR_RADIUS 10.f
#define MAX_SIGMA 6.f
typedef enum
{
@ -154,7 +153,7 @@ typedef struct
{
FramebufferData data;
BlurType type;
int blur_radius_uniform;
int sigma_uniform;
int pixel_step_uniform;
int vertical_uniform;
} BlurData;
@ -182,14 +181,14 @@ struct _ShellBlurEffect
ShellBlurMode mode;
float downscale_factor;
float brightness;
int blur_radius;
int sigma;
};
G_DEFINE_TYPE (ShellBlurEffect, shell_blur_effect, CLUTTER_TYPE_EFFECT)
enum {
PROP_0,
PROP_BLUR_RADIUS,
PROP_SIGMA,
PROP_BRIGHTNESS,
PROP_MODE,
N_PROPS
@ -272,8 +271,8 @@ setup_blur (BlurData *blur,
blur->type = type;
blur->data.pipeline = create_blur_pipeline ();
blur->blur_radius_uniform =
cogl_pipeline_get_uniform_location (blur->data.pipeline, "blur_radius");
blur->sigma_uniform =
cogl_pipeline_get_uniform_location (blur->data.pipeline, "sigma");
blur->pixel_step_uniform =
cogl_pipeline_get_uniform_location (blur->data.pipeline, "pixel_step");
blur->vertical_uniform =
@ -300,11 +299,11 @@ update_blur_uniforms (ShellBlurEffect *self,
pixel_step);
}
if (blur->blur_radius_uniform > -1)
if (blur->sigma_uniform > -1)
{
cogl_pipeline_set_uniform_1f (blur->data.pipeline,
blur->blur_radius_uniform,
self->blur_radius / self->downscale_factor);
blur->sigma_uniform,
self->sigma / self->downscale_factor);
}
if (blur->vertical_uniform > -1)
@ -462,18 +461,18 @@ clear_framebuffer_data (FramebufferData *fb_data)
static float
calculate_downscale_factor (float width,
float height,
float blur_radius)
float sigma)
{
float downscale_factor = 1.0;
float scaled_width = width;
float scaled_height = height;
float scaled_radius = blur_radius;
float scaled_sigma = sigma;
/* This is the algorithm used by Firefox; keep downscaling until either the
* blur radius is lower than the threshold, or the downscaled texture is too
* small.
*/
while (scaled_radius > MAX_BLUR_RADIUS &&
while (scaled_sigma > MAX_SIGMA &&
scaled_width > MIN_DOWNSCALE_SIZE &&
scaled_height > MIN_DOWNSCALE_SIZE)
{
@ -481,7 +480,7 @@ calculate_downscale_factor (float width,
scaled_width = width / downscale_factor;
scaled_height = height / downscale_factor;
scaled_radius = blur_radius / downscale_factor;
scaled_sigma = sigma / downscale_factor;
}
return downscale_factor;
@ -689,7 +688,7 @@ update_framebuffers (ShellBlurEffect *self)
return FALSE;
get_target_size (self, &width, &height);
downscale_factor = calculate_downscale_factor (width, height, self->blur_radius);
downscale_factor = calculate_downscale_factor (width, height, self->sigma);
updated =
update_actor_fbo (self, width, height, downscale_factor) &&
@ -777,7 +776,7 @@ shell_blur_effect_paint (ClutterEffect *effect,
ShellBlurEffect *self = SHELL_BLUR_EFFECT (effect);
uint8_t paint_opacity;
if (self->blur_radius > 0)
if (self->sigma > 0)
{
if (needs_repaint (self, flags))
{
@ -841,11 +840,11 @@ shell_blur_effect_modify_paint_volume (ClutterEffect *effect,
width = clutter_paint_volume_get_width (volume);
height = clutter_paint_volume_get_height (volume);
origin.y -= self->blur_radius;
origin.x -= self->blur_radius;
origin.y -= self->sigma;
origin.x -= self->sigma;
height += 2 * self->blur_radius;
width += 2 * self->blur_radius;
height += 2 * self->sigma;
width += 2 * self->sigma;
clutter_paint_volume_set_origin (volume, &origin);
clutter_paint_volume_set_width (volume, width);
@ -884,8 +883,8 @@ shell_blur_effect_get_property (GObject *object,
switch (prop_id)
{
case PROP_BLUR_RADIUS:
g_value_set_int (value, self->blur_radius);
case PROP_SIGMA:
g_value_set_int (value, self->sigma);
break;
case PROP_BRIGHTNESS:
@ -911,8 +910,8 @@ shell_blur_effect_set_property (GObject *object,
switch (prop_id)
{
case PROP_BLUR_RADIUS:
shell_blur_effect_set_blur_radius (self, g_value_get_int (value));
case PROP_SIGMA:
shell_blur_effect_set_sigma (self, g_value_get_int (value));
break;
case PROP_BRIGHTNESS:
@ -944,10 +943,10 @@ shell_blur_effect_class_init (ShellBlurEffectClass *klass)
effect_class->paint = shell_blur_effect_paint;
effect_class->modify_paint_volume = shell_blur_effect_modify_paint_volume;
properties[PROP_BLUR_RADIUS] =
g_param_spec_int ("blur-radius",
"Blur radius",
"Blur radius",
properties[PROP_SIGMA] =
g_param_spec_int ("sigma",
"Sigma",
"Sigma",
0, G_MAXINT, 0,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
@ -973,7 +972,7 @@ static void
shell_blur_effect_init (ShellBlurEffect *self)
{
self->mode = SHELL_BLUR_MODE_ACTOR;
self->blur_radius = 0;
self->sigma = 0;
self->brightness = 1.f;
self->actor_fb.pipeline = create_base_pipeline ();
@ -993,29 +992,29 @@ shell_blur_effect_new (void)
}
int
shell_blur_effect_get_blur_radius (ShellBlurEffect *self)
shell_blur_effect_get_sigma (ShellBlurEffect *self)
{
g_return_val_if_fail (SHELL_IS_BLUR_EFFECT (self), -1);
return self->blur_radius;
return self->sigma;
}
void
shell_blur_effect_set_blur_radius (ShellBlurEffect *self,
int radius)
shell_blur_effect_set_sigma (ShellBlurEffect *self,
int sigma)
{
g_return_if_fail (SHELL_IS_BLUR_EFFECT (self));
if (self->blur_radius == radius)
if (self->sigma == sigma)
return;
self->blur_radius = radius;
self->sigma = sigma;
self->cache_flags &= ~BLUR_APPLIED;
if (self->actor)
clutter_effect_queue_repaint (CLUTTER_EFFECT (self));
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_BLUR_RADIUS]);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SIGMA]);
}
float

6
src/shell-blur-effect.h
View File

@ -42,9 +42,9 @@ G_DECLARE_FINAL_TYPE (ShellBlurEffect, shell_blur_effect, SHELL, BLUR_EFFECT, Cl
ShellBlurEffect *shell_blur_effect_new (void);
int shell_blur_effect_get_blur_radius (ShellBlurEffect *self);
void shell_blur_effect_set_blur_radius (ShellBlurEffect *self,
int radius);
int shell_blur_effect_get_sigma (ShellBlurEffect *self);
void shell_blur_effect_set_sigma (ShellBlurEffect *self,
int sigma);
float shell_blur_effect_get_brightness (ShellBlurEffect *self);
void shell_blur_effect_set_brightness (ShellBlurEffect *self,