fix(lib: gears: color): use surface for recolor

lib/gears/color.lua

@@ -286,9 +286,13 @@ function color.create_opaque_pattern(col)
     -- gradients can do weird self-intersections)
 end
 
+--- Fill non-transparent area of an image with a given color.
+-- @param image Image or path to it.
+-- @param new_color New color.
+-- @return Recolored image.
 function color.recolor_image(image, new_color)
     if type(image) == 'string' then
-        image = cairo.ImageSurface.create_from_png(image)
+        image = surface.duplicate_surface(image)
     end
     local cr = cairo.Context.create(image)
     cr:set_source(color.create_pattern(new_color))

lib/gears/surface.lua

@@ -70,6 +70,27 @@ function surface.get_size(surf)
     return w - x, h - y
 end
 
+
+--- Get the duplicate of a cairo surface
+-- @param s Source surface.
+-- @return The surface's duplicate.
+function surface.duplicate_surface(s)
+    s = surface.load(s)
+
+    -- Figure out surface size (this does NOT work for unbounded recording surfaces)
+    local cr = cairo.Context(s)
+    local x, y, w, h = cr:clip_extents()
+
+    -- Create a copy
+    local result = s:create_similar(s.content, w - x, h - y)
+    cr = cairo.Context(result)
+    cr:set_source_surface(s, 0, 0)
+    cr.operator = cairo.Operator.SOURCE
+    cr:paint()
+    return result
+end
+
+
 return setmetatable(surface, surface.mt)
 
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