backend: add new image property: corner radius

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/backend/backend.h

@@ -36,6 +36,7 @@ typedef void (*backend_ready_callback_t)(void *);
 // particular order:
 //
 // Color inversion -> Dimming -> Opacity multiply -> Limit maximum brightness
+// (Corner radius could be applied in any order)
 enum image_properties {
 	// Whether the color of the image is inverted
 	// 1 boolean, default: false
@@ -54,6 +55,9 @@ enum image_properties {
 	// brightness down to the max brightness value.
 	// 1 double, default: 1
 	IMAGE_PROPERTY_MAX_BRIGHTNESS,
+	// Gives the image a rounded corner.
+	// 1 double, default: 0
+	IMAGE_PROPERTY_CORNER_RADIUS,
 };
 
 enum image_operations {

src/backend/backend_common.c

@@ -449,6 +449,7 @@ bool default_set_image_property(backend_t *base attr_unused, enum image_properti
 		tex->ewidth = iargs[0];
 		tex->eheight = iargs[1];
 		break;
+	case IMAGE_PROPERTY_CORNER_RADIUS: tex->corner_radius = dargs[0]; break;
 	case IMAGE_PROPERTY_MAX_BRIGHTNESS: tex->max_brightness = dargs[0]; break;
 	}
 

src/backend/backend_common.h

@@ -37,6 +37,7 @@ struct backend_image {
 	double opacity;
 	double dim;
 	double max_brightness;
+	double corner_radius;
 	// Effective size of the image
 	int ewidth, eheight;
 	bool color_inverted;