Implement an "emboss" filter in the worst way known to mankind (#308)

src/meson.build

@@ -91,6 +91,7 @@ drawing_sources = [
 	'tools/transform_tools/filters/filter_blur.py',
 	'tools/transform_tools/filters/filter_colors.py',
 	'tools/transform_tools/filters/filter_contrast.py',
+	'tools/transform_tools/filters/filter_emboss.py',
 	'tools/transform_tools/filters/filter_saturation.py',
 	'tools/transform_tools/filters/filter_transparency.py',
 	'tools/transform_tools/filters/filter_veil.py',

src/optionsbars/transform/optionsbar-filters.ui

@@ -116,6 +116,11 @@
         <attribute name="action">win.filters_type</attribute>
         <attribute name="target">contrast</attribute>
       </item>
+      <item>
+        <attribute name="label" translatable="yes">Emboss</attribute>
+        <attribute name="action">win.filters_type</attribute>
+        <attribute name="target">emboss</attribute>
+      </item>
     </section>
     <section>
       <!-- Context: the title of the menu with various types of blurring -->

src/tools/transform_tools/filters/filter_emboss.py

@@ -0,0 +1,41 @@
+# Licensed under GPL3 https://github.com/maoschanz/drawing/blob/master/LICENSE
+
+import cairo
+from gi.repository import Gdk
+from .abstract_filter import AbstractFilter
+from .utilities_blur import utilities_blur_surface, BlurType, BlurDirection
+
+class FilterEmboss(AbstractFilter):
+	__gtype_name__ = 'FilterEmboss'
+
+	def do_filter_operation(self, source_pixbuf, operation):
+		surface = Gdk.cairo_surface_create_from_pixbuf(source_pixbuf, 0, None)
+		scale = self._tool.scale_factor()
+		surface.set_device_scale(scale, scale)
+		width = source_pixbuf.get_width()
+		height = source_pixbuf.get_height()
+		new_surface = cairo.ImageSurface(cairo.Format.ARGB32, width, height)
+
+		cairo_context = cairo.Context(new_surface)
+		cairo_context.set_source_surface(surface)
+		cairo_context.set_operator(cairo.Operator.SOURCE)
+		cairo_context.paint()
+
+		bdir = BlurDirection.BOTH # could be an option
+		bs = utilities_blur_surface(surface, 1, BlurType.CAIRO_REPAINTS, bdir)
+		cairo_context2 = cairo.Context(bs)
+		cairo_context2.set_operator(cairo.Operator.DIFFERENCE)
+		cairo_context2.set_source_rgba(1.0, 1.0, 1.0, 1.0)
+		cairo_context2.paint()
+
+		cairo_context.set_source_surface(bs)
+		cairo_context.set_operator(cairo.Operator.OVER)
+		cairo_context.paint_with_alpha(0.5)
+
+		new_pixbuf = Gdk.pixbuf_get_from_surface(new_surface, 0, 0, \
+		                      new_surface.get_width(), new_surface.get_height())
+		self._tool.get_image().set_temp_pixbuf(new_pixbuf)
+
+	############################################################################
+################################################################################
+

src/tools/transform_tools/filters/filter_transparency.py

@@ -39,8 +39,8 @@ def do_filter_operation(self, source_pixbuf, operation):
 		new_surface = cairo.ImageSurface(cairo.Format.ARGB32, width, height)
 		cairo_context = cairo.Context(new_surface)
 		cairo_context.set_source_surface(surface)
-
 		cairo_context.set_operator(cairo.Operator.SOURCE)
+
 		cairo_context.paint_with_alpha(1.0 - percent)
 		# TODO if percent is negative, paint first the normal version, and then
 		# paint with [-1 * percent] alpha the pixbuf

src/tools/transform_tools/tool_filters.py

@@ -21,6 +21,7 @@
 from .filter_blur import FilterBlur
 from .filter_colors import FilterColors
 from .filter_contrast import FilterContrast
+from .filter_emboss import FilterEmboss
 from .filter_saturation import FilterSaturation
 from .filter_transparency import FilterTransparency
 from .filter_veil import FilterVeil
@@ -48,6 +49,7 @@ def __init__(self, window):
 			'blur': FilterBlur('blur', self),
 			'colors': FilterColors('colors', self),
 			'contrast': FilterContrast('contrast', self),
+			'emboss': FilterEmboss('emboss', self),
 			'saturation': FilterSaturation('saturation', self),
 			'transparency': FilterTransparency('transparency', self),
 			'veil': FilterVeil('veil', self),
@@ -110,6 +112,9 @@ def _set_active_type(self, *args):
 			self.type_label = _("Increase contrast")
 			self._active_filter = 'contrast'
 		# TODO changer la luminosity tant qu'à faire
+		elif state_as_string == 'emboss':
+			self.type_label = _("Emboss")
+			self._active_filter = 'emboss'
 
 		elif state_as_string == 'invert':
 			self.type_label = _("Invert colors")

src/tools/ui/tool-filters.ui

@@ -30,6 +30,11 @@
             <attribute name="action">win.filters_type</attribute>
             <attribute name="target">contrast</attribute>
           </item>
+          <item>
+            <attribute name="label" translatable="yes">Emboss</attribute>
+            <attribute name="action">win.filters_type</attribute>
+            <attribute name="target">emboss</attribute>
+          </item>
         </section>
         <section>
           <item>