lib/squib/graphics/save_images.rb in squib-0.16.0 vs lib/squib/graphics/save_images.rb in squib-0.17.0

@@ -1,52 +1,91 @@
+require_relative 'cairo_context_wrapper'
+
 module Squib
   class Card
 
     # :nodoc:
     # @api private
-    def save_png(batch)
-      surface = if preprocess_save?(batch)
+    def save_png(batch, shadow)
+      surface = if preprocess_save?(batch, shadow)
                   w, h = compute_dimensions(batch.rotate, batch.trim)
-                  preprocessed_save(w, h, batch)
+                  preprocessed_save(w, h, batch, shadow)
                 else
                   @cairo_surface
                 end
       write_png(surface, index, batch)
     end
 
     # :nodoc:
     # @api private
-    def preprocess_save?(batch)
-      batch.rotate != false || batch.trim > 0
+    def preprocess_save?(batch, shadow)
+      batch.rotate != false || batch.trim > 0 || !(shadow.shadow_radius.nil?)
     end
 
     def compute_dimensions(rotate, trim)
       if rotate
         [ @height - 2 * trim, @width - 2 * trim ]
       else
         [ @width - 2 * trim, @height - 2 * trim ]
       end
     end
 
-    def preprocessed_save(width, height, batch)
-      new_cc = Cairo::Context.new(Cairo::ImageSurface.new(width, height))
+    def preprocessed_save(w, h, batch, shadow)
+      new_cc = Cairo::Context.new(Cairo::ImageSurface.new(w, h))
       trim_radius = batch.trim_radius
       if batch.rotate != false
-        new_cc.translate(width * 0.5, height * 0.5)
-        new_cc.rotate(batch.angle)
-        new_cc.translate(height * -0.5, width * -0.5)
-        new_cc.rounded_rectangle(0, 0, height, width, trim_radius, trim_radius)
+        new_cc.translate w * 0.5, h * 0.5
+        new_cc.rotate batch.angle
+        new_cc.translate h * -0.5, w * -0.5
+        new_cc.rounded_rectangle(0, 0, h, w, trim_radius, trim_radius)
       else
-        new_cc.rounded_rectangle(0, 0, width, height, trim_radius, trim_radius)
+        new_cc.rounded_rectangle(0, 0, w, h, trim_radius, trim_radius)
       end
       new_cc.clip
       new_cc.set_source(@cairo_surface, -batch.trim, -batch.trim)
       new_cc.paint
+      new_cc.reset_clip
+      new_cc = drop_shadow(new_cc, shadow, batch) unless shadow.shadow_radius.nil?
       return new_cc.target
     end
 
+    # pseudo-blur behave weirdly with a radius of 0 - wrapping
+    def blur(cc, r, &block)
+      if r == 0
+        yield(block)
+      else
+        cc.pseudo_blur(r, &block)
+      end
+    end
+
+    def drop_shadow(cc, s, batch)
+      off_x = s.shadow_offset_x
+      off_y = s.shadow_offset_y
+      s_trim = s.shadow_trim
+      s_rad = s.shadow_radius
+      new_w = cc.target.width  + off_x + 3 * s_rad - (2 * s_trim)
+      new_h = cc.target.height + off_y + 3 * s_rad - (2 * s_trim)
+      new_cc = Squib::Graphics::CairoContextWrapper.new(
+        Cairo::Context.new(Cairo::ImageSurface.new(new_w, new_h)))
+      blur(new_cc, s_rad) do
+        # fill in with shadow color
+        new_cc.set_source_squibcolor s.shadow_color
+        new_cc.rectangle 0, 0, new_cc.target.width, new_cc.target.height
+        new_cc.fill
+        # then, paint but blend with :dest_in to get a shadow-shaped drawing
+        new_cc.set_source cc.target, s_rad + off_x, s_rad + off_y
+        new_cc.operator = :dest_in # see https://www.cairographics.org/operators/
+        new_cc.paint
+      end
+      new_cc.set_source cc.target, s_rad, s_rad
+      new_cc.operator = :over
+      new_cc.paint
+      return new_cc
+    end
+
     def write_png(surface, i, b)
-      surface.write_to_png("#{b.dir}/#{b.prefix}#{b.count_format % i}#{b.suffix}.png")
+      filename = "#{b.dir}/#{b.prefix}#{b.count_format % i}#{b.suffix}.png"
+      surface.write_to_png filename
     end
 
   end
 end