Move swaybg background rendering into common/

swaylock will use it too

1 files changed, 100 insertions, 0 deletions

diff --git a/common/background-image.c b/common/background-image.c
new file mode 100644
index 00000000..2988c2e2
--- /dev/null
+++ b/common/background-image.c
@@ -0,0 +1,100 @@
+#include <assert.h>
+#include <stdbool.h>
+#include <wlr/util/log.h>
+#include "background-image.h"
+#include "cairo.h"
+
+cairo_surface_t *load_background_image(const char *path) {
+        cairo_surface_t *image;
+#ifdef HAVE_GDK_PIXBUF
+        GError *err = NULL;
+        GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file(path, &err);
+        if (!pixbuf) {
+                wlr_log(L_ERROR, "Failed to load background image.");
+                return false;
+        }
+        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) {
+                wlr_log(L_ERROR, "Failed to read background image.");
+                return NULL;
+        }
+        if (cairo_surface_status(image) != CAIRO_STATUS_SUCCESS) {
+                wlr_log(L_ERROR, "Failed to read background image: %s."
+#ifndef 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,
+                int buffer_scale) {
+        double width = cairo_image_surface_get_width(image);
+        double height = cairo_image_surface_get_height(image);
+
+        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:
+                assert(0);
+                break;
+        }
+        cairo_paint(cairo);
+}