#include <assert.h>
#include "background-image.h"
#include "cairo.h"
#include "log.h"
#if HAVE_GDK_PIXBUF
#include <gdk-pixbuf/gdk-pixbuf.h>
#endif
enum background_mode parse_background_mode(const char *mode) {
if (strcmp(mode, "stretch") == 0) {
return BACKGROUND_MODE_STRETCH;
} else if (strcmp(mode, "fill") == 0) {
return BACKGROUND_MODE_FILL;
} else if (strcmp(mode, "fit") == 0) {
return BACKGROUND_MODE_FIT;
} else if (strcmp(mode, "center") == 0) {
return BACKGROUND_MODE_CENTER;
} else if (strcmp(mode, "tile") == 0) {
return BACKGROUND_MODE_TILE;
} else if (strcmp(mode, "solid_color") == 0) {
return BACKGROUND_MODE_SOLID_COLOR;
}
sway_log(SWAY_ERROR, "Unsupported background mode: %s", mode);
return BACKGROUND_MODE_INVALID;
}
#if HAVE_GDK_PIXBUF
static cairo_surface_t* gdk_cairo_image_surface_create_from_pixbuf(
const GdkPixbuf *gdkbuf) {
int chan = gdk_pixbuf_get_n_channels(gdkbuf);
if (chan < 3) {
return NULL;
}
const guint8* gdkpix = gdk_pixbuf_read_pixels(gdkbuf);
if (!gdkpix) {
return NULL;
}
gint w = gdk_pixbuf_get_width(gdkbuf);
gint h = gdk_pixbuf_get_height(gdkbuf);
int stride = gdk_pixbuf_get_rowstride(gdkbuf);
cairo_format_t fmt = (chan == 3) ? CAIRO_FORMAT_RGB24 : CAIRO_FORMAT_ARGB32;
cairo_surface_t * cs = cairo_image_surface_create (fmt, w, h);
cairo_surface_flush (cs);
if ( !cs || cairo_surface_status(cs) != CAIRO_STATUS_SUCCESS) {
return NULL;
}
int cstride = cairo_image_surface_get_stride(cs);
unsigned char * cpix = cairo_image_surface_get_data(cs);
if (chan == 3) {
int i;
for (i = h; i; --i) {
const guint8 *gp = gdkpix;
unsigned char *cp = cpix;
const guint8* end = gp + 3*w;
while (gp < end) {
#if G_BYTE_ORDER == G_LITTLE_ENDIAN
cp[0] = gp[2];
cp[1] = gp[1];
cp[2] = gp[0];
#else
cp[1] = gp[0];
cp[2] = gp[1];
cp[3] = gp[2];
#endif
gp += 3;
cp += 4;
}
gdkpix += stride;
cpix += cstride;
}
} else {
/* premul-color = alpha/255 * color/255 * 255 = (alpha*color)/255
* (z/255) = z/256 * 256/255 = z/256 (1 + 1/255)
* = z/256 + (z/256)/255 = (z + z/255)/256
* # recurse once
* = (z + (z + z/255)/256)/256
* = (z + z/256 + z/256/255) / 256
* # only use 16bit uint operations, loose some precision,
* # result is floored.
* -> (z + z>>8)>>8
* # add 0x80/255 = 0.5 to convert floor to round
* => (z+0x80 + (z+0x80)>>8 ) >> 8
* ------
* tested as equal to lround(z/255.0) for uint z in [0..0xfe02]
*/
#define PREMUL_ALPHA(x,a,b,z) \
G_STMT_START { z = a * b + 0x80; x = (z + (z >> 8)) >> 8; } \
G_STMT_END
int i;
for (i = h; i; --i) {
const guint8 *gp = gdkpix;
unsigned char *cp = cpix;
const guint8* end = gp + 4*w;
guint z1, z2, z3;
while (gp < end) {
#if G_BYTE_ORDER == G_LITTLE_ENDIAN
PREMUL_ALPHA(cp[0], gp[2], gp[3], z1);
PREMUL_ALPHA(cp[1], gp[1], gp[3], z2);
PREMUL_ALPHA(cp[2], gp[0], gp[3], z3);
cp[3] = gp[3];
#else
PREMUL_ALPHA(cp[1], gp[0], gp[3], z1);
PREMUL_ALPHA(cp[2], gp[1], gp[3], z2);
PREMUL_ALPHA(cp[3], gp[2], gp[3], z3);
cp[0] = gp[3];
#endif
gp += 4;
cp += 4;
}
gdkpix += stride;
cpix += cstride;
}
#undef PREMUL_ALPHA
}
cairo_surface_mark_dirty(cs);
return cs;
}
#endif // HAVE_GDK_PIXBUF
cairo_surface_t *load_background_image(const char *path) {
cairo_surface_t *image;
#if HAVE_GDK_PIXBUF
GError *err = NULL;
GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file(path, &err);
if (!pixbuf) {
sway_log(SWAY_ERROR, "Failed to load background image (%s).",
err->message);
return NULL;
}
image = gdk_cairo_image_surface_create_from_pixbuf(pixbuf);
g_object_unref(pixbuf);
#else
image = cairo_image_surface_create_from_png(path);
#endif // HAVE_GDK_PIXBUF
if (!image) {
sway_log(SWAY_ERROR, "Failed to read background image.");
return NULL;
}
if (cairo_surface_status(image) != CAIRO_STATUS_SUCCESS) {
sway_log(SWAY_ERROR, "Failed to read background image: %s."
#if !HAVE_GDK_PIXBUF
"\nSway was compiled without gdk_pixbuf support, so only"
"\nPNG images can be loaded. This is the likely cause."
#endif // !HAVE_GDK_PIXBUF
, cairo_status_to_string(cairo_surface_status(image)));
return NULL;
}
return image;
}
void render_background_image(cairo_t *cairo, cairo_surface_t *image,
enum background_mode mode, int buffer_width, int buffer_height) {
double width = cairo_image_surface_get_width(image);
double height = cairo_image_surface_get_height(image);
cairo_save(cairo);
switch (mode) {
case BACKGROUND_MODE_STRETCH:
cairo_scale(cairo,
(double)buffer_width / width,
(double)buffer_height / height);
cairo_set_source_surface(cairo, image, 0, 0);
break;
case BACKGROUND_MODE_FILL: {
double window_ratio = (double)buffer_width / buffer_height;
double bg_ratio = width / height;
if (window_ratio > bg_ratio) {
double scale = (double)buffer_width / width;
cairo_scale(cairo, scale, scale);
cairo_set_source_surface(cairo, image,
0, (double)buffer_height / 2 / scale - height / 2);
} else {
double scale = (double)buffer_height / height;
cairo_scale(cairo, scale, scale);
cairo_set_source_surface(cairo, image,
(double)buffer_width / 2 / scale - width / 2, 0);
}
break;
}
case BACKGROUND_MODE_FIT: {
double window_ratio = (double)buffer_width / buffer_height;
double bg_ratio = width / height;
if (window_ratio > bg_ratio) {
double scale = (double)buffer_height / height;
cairo_scale(cairo, scale, scale);
cairo_set_source_surface(cairo, image,
(double)buffer_width / 2 / scale - width / 2, 0);
} else {
double scale = (double)buffer_width / width;
cairo_scale(cairo, scale, scale);
cairo_set_source_surface(cairo, image,
0, (double)buffer_height / 2 / scale - height / 2);
}
break;
}
case BACKGROUND_MODE_CENTER:
cairo_set_source_surface(cairo, image,
(double)buffer_width / 2 - width / 2,
(double)buffer_height / 2 - height / 2);
break;
case BACKGROUND_MODE_TILE: {
cairo_pattern_t *pattern = cairo_pattern_create_for_surface(image);
cairo_pattern_set_extend(pattern, CAIRO_EXTEND_REPEAT);
cairo_set_source(cairo, pattern);
break;
}
case BACKGROUND_MODE_SOLID_COLOR:
case BACKGROUND_MODE_INVALID:
assert(0);
break;
}
cairo_paint(cairo);
cairo_restore(cairo);
}
