[gnome-photos/gnome-3-24] Use our own composer for the SVG (and PDF) blend operation multiply

[Debarshi Ray <debarshir src gnome org>]

commit f859aa71b4537d5a787d89689757a5ede602f7d4
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Jun 21 17:19:56 2017 +0200

    Use our own composer for the SVG (and PDF) blend operation multiply
    
    The svg:multiply operation got removed in GEGL 0.3.16 due to conflicts
    with gegl:multiply. Even though gegl:multiply is intended to produce
    the same result as svg:multiply, that is not the case right now. They
    only match when the auxiliary and input buffers don't have any
    transparency.
    
    Let's implement and carry our own until this is resolved.
    
    Based on:
    https://www.cairographics.org/operators/
    https://www.w3.org/TR/2004/WD-SVG12-20041027/rendering.html#comp-op-prop

 src/Makefile.am                     |    4 +
 src/photos-gegl.c                   |    2 +
 src/photos-operation-insta-hefe.c   |    2 +-
 src/photos-operation-svg-multiply.c |  223 +++++++++++++++++++++++++++++++++++
 src/photos-operation-svg-multiply.h |   39 ++++++
 5 files changed, 269 insertions(+), 1 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index b8e6951..0348f02 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -160,6 +160,8 @@ gnome_photos_SOURCES = \
        photos-operation-png-guess-sizes.h \
        photos-operation-saturation.c \
        photos-operation-saturation.h \
+       photos-operation-svg-multiply.c \
+       photos-operation-svg-multiply.h \
        photos-organize-collection-dialog.c \
        photos-organize-collection-dialog.h \
        photos-organize-collection-model.c \
@@ -324,6 +326,8 @@ gnome_photos_thumbnailer_SOURCES = \
        photos-operation-png-guess-sizes.h \
        photos-operation-saturation.c \
        photos-operation-saturation.h \
+       photos-operation-svg-multiply.c \
+       photos-operation-svg-multiply.h \
        photos-pipeline.c \
        photos-pipeline.h \
        photos-pixbuf.c \
diff --git a/src/photos-gegl.c b/src/photos-gegl.c
index 9080490..d943608 100644
--- a/src/photos-gegl.c
+++ b/src/photos-gegl.c
@@ -31,6 +31,7 @@
 #include "photos-operation-jpg-guess-sizes.h"
 #include "photos-operation-png-guess-sizes.h"
 #include "photos-operation-saturation.h"
+#include "photos-operation-svg-multiply.h"
 #include "photos-quarks.h"
 
 
@@ -228,6 +229,7 @@ photos_gegl_ensure_builtins (void)
       g_type_ensure (PHOTOS_TYPE_OPERATION_JPG_GUESS_SIZES);
       g_type_ensure (PHOTOS_TYPE_OPERATION_PNG_GUESS_SIZES);
       g_type_ensure (PHOTOS_TYPE_OPERATION_SATURATION);
+      g_type_ensure (PHOTOS_TYPE_OPERATION_SVG_MULTIPLY);
 
       g_once_init_leave (&once_init_value, 1);
     }
diff --git a/src/photos-operation-insta-hefe.c b/src/photos-operation-insta-hefe.c
index 5f423c0..fe7e492 100644
--- a/src/photos-operation-insta-hefe.c
+++ b/src/photos-operation-insta-hefe.c
@@ -69,7 +69,7 @@ photos_operation_insta_hefe_attach (GeglOperation *operation)
   self->output = gegl_node_get_output_proxy (operation->node, "output");
 
   curve = gegl_node_new_child (operation->node, "operation", "photos:insta-hefe-curve", NULL);
-  multiply = gegl_node_new_child (operation->node, "operation", "svg:multiply", "srgb", TRUE, NULL);
+  multiply = gegl_node_new_child (operation->node, "operation", "photos:svg-multiply", "srgb", TRUE, NULL);
   self->vignette = gegl_node_new_child (operation->node, "operation", "photos:insta-hefe-vignette", NULL);
 
   gegl_node_connect_to (self->vignette, "output", multiply, "aux");
diff --git a/src/photos-operation-svg-multiply.c b/src/photos-operation-svg-multiply.c
new file mode 100644
index 0000000..e1a2394
--- /dev/null
+++ b/src/photos-operation-svg-multiply.c
@@ -0,0 +1,223 @@
+/*
+ * Photos - access, organize and share your photos on GNOME
+ * Copyright © 2017 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+
+#include "config.h"
+
+#include <babl/babl.h>
+#include <gegl.h>
+
+#include "photos-operation-svg-multiply.h"
+
+
+struct _PhotosOperationSvgMultiply
+{
+  GeglOperationPointComposer parent_instance;
+  gboolean srgb;
+};
+
+enum
+{
+  PROP_0,
+  PROP_SRGB
+};
+
+
+G_DEFINE_TYPE (PhotosOperationSvgMultiply, photos_operation_svg_multiply, 
GEGL_TYPE_OPERATION_POINT_COMPOSER);
+
+
+static void
+photos_operation_svg_multiply_prepare (GeglOperation *operation)
+{
+  PhotosOperationSvgMultiply *self = PHOTOS_OPERATION_SVG_MULTIPLY (operation);
+  const Babl *format;
+
+  if (self->srgb)
+    format = babl_format ("R'aG'aB'aA float");
+  else
+    format = babl_format ("RaGaBaA float");
+
+  gegl_operation_set_format (operation, "aux", format);
+  gegl_operation_set_format (operation, "input", format);
+  gegl_operation_set_format (operation, "output", format);
+}
+
+
+static gboolean
+photos_operation_svg_multiply_operation_process (GeglOperation *operation,
+                                                 GeglOperationContext *context,
+                                                 const gchar *output_pad,
+                                                 const GeglRectangle *roi,
+                                                 gint level)
+{
+  GObject *aux;
+  GObject *input;
+  const GeglRectangle *aux_bbox = NULL;
+  const GeglRectangle *in_bbox = NULL;
+  gboolean ret_val = TRUE;
+
+  aux = gegl_operation_context_get_object (context, "aux");
+  if (aux != NULL)
+    aux_bbox = gegl_buffer_get_abyss (GEGL_BUFFER (aux));
+
+  input = gegl_operation_context_get_object (context, "input");
+  if (input != NULL)
+    in_bbox = gegl_buffer_get_abyss (GEGL_BUFFER (input));
+
+  if (aux == NULL || (input != NULL && !gegl_rectangle_intersect (NULL, aux_bbox, roi)))
+    {
+      gegl_operation_context_set_object (context, "output", input);
+      goto out;
+    }
+
+  if (input == NULL || (aux != NULL && !gegl_rectangle_intersect (NULL, in_bbox, roi)))
+    {
+      gegl_operation_context_set_object (context, "output", aux);
+      goto out;
+    }
+
+  ret_val = GEGL_OPERATION_CLASS (photos_operation_svg_multiply_parent_class)->process (operation,
+                                                                                        context,
+                                                                                        output_pad,
+                                                                                        roi,
+                                                                                        level);
+
+ out:
+  return ret_val;
+}
+
+
+static gboolean
+photos_operation_svg_multiply_point_composer_process (GeglOperation *operation,
+                                                      void *in_buf,
+                                                      void *aux_buf,
+                                                      void *out_buf,
+                                                      glong n_pixels,
+                                                      const GeglRectangle *roi,
+                                                      gint level)
+{
+  gfloat *aux = aux_buf;
+  gfloat *in = in_buf;
+  gfloat *out = out_buf;
+  glong i;
+
+  g_return_val_if_fail (aux != NULL, FALSE);
+  g_return_val_if_fail (in != NULL, FALSE);
+
+  for (i = 0; i < n_pixels; i++)
+    {
+      const gfloat aA = aux[3];
+      const gfloat aB = in[3];
+      const gfloat aR = aA + aB * (1 - aA);
+      gint j;
+
+      out[3] = aR;
+
+      for (j = 0; j < 3; j++)
+        {
+          const gfloat xA = aux[j];
+          const gfloat xB = in[j];
+          gfloat xR;
+
+          xR = (1 - aB) * xA + (1 - aA) * xB + xA * xB;
+          out[j] = CLAMP (xR, 0.0f, aR);
+        }
+
+      aux += 4;
+      in += 4;
+      out += 4;
+    }
+
+  return TRUE;
+}
+
+
+static void
+photos_operation_svg_multiply_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
+{
+  PhotosOperationSvgMultiply *self = PHOTOS_OPERATION_SVG_MULTIPLY (object);
+
+  switch (prop_id)
+    {
+    case PROP_SRGB:
+      g_value_set_boolean (value, self->srgb);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+
+static void
+photos_operation_svg_multiply_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec 
*pspec)
+{
+  PhotosOperationSvgMultiply *self = PHOTOS_OPERATION_SVG_MULTIPLY (object);
+
+  switch (prop_id)
+    {
+    case PROP_SRGB:
+      self->srgb = g_value_get_boolean (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+
+static void
+photos_operation_svg_multiply_init (PhotosOperationSvgMultiply *self)
+{
+}
+
+
+static void
+photos_operation_svg_multiply_class_init (PhotosOperationSvgMultiplyClass *class)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+  GeglOperationClass *operation_class = GEGL_OPERATION_CLASS (class);
+  GeglOperationPointComposerClass *point_composer_class = GEGL_OPERATION_POINT_COMPOSER_CLASS (class);
+
+  operation_class->opencl_support = FALSE;
+
+  object_class->get_property = photos_operation_svg_multiply_get_property;
+  object_class->set_property = photos_operation_svg_multiply_set_property;
+  operation_class->prepare = photos_operation_svg_multiply_prepare;
+  operation_class->process = photos_operation_svg_multiply_operation_process;
+  point_composer_class->process = photos_operation_svg_multiply_point_composer_process;
+
+  g_object_class_install_property (object_class,
+                                   PROP_SRGB,
+                                   g_param_spec_boolean ("srgb",
+                                                         "sRGB",
+                                                         "Use sRGB gamma instead of linear",
+                                                         FALSE,
+                                                         G_PARAM_CONSTRUCT | G_PARAM_READWRITE));
+
+  gegl_operation_class_set_keys (operation_class,
+                                 "name", "photos:svg-multiply",
+                                 "title", "SVG Multiply",
+                                 "description", "SVG blend operation multiply",
+                                 "categories", "compositors:svgfilter",
+                                 NULL);
+}
diff --git a/src/photos-operation-svg-multiply.h b/src/photos-operation-svg-multiply.h
new file mode 100644
index 0000000..0aa0357
--- /dev/null
+++ b/src/photos-operation-svg-multiply.h
@@ -0,0 +1,39 @@
+/*
+ * Photos - access, organize and share your photos on GNOME
+ * Copyright © 2017 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef PHOTOS_OPERATION_SVG_MULTIPLY_H
+#define PHOTOS_OPERATION_SVG_MULTIPLY_H
+
+#include <gegl-plugin.h>
+
+#include "photos-gegl.h"
+
+G_BEGIN_DECLS
+
+#define PHOTOS_TYPE_OPERATION_SVG_MULTIPLY (photos_operation_svg_multiply_get_type ())
+G_DECLARE_FINAL_TYPE (PhotosOperationSvgMultiply,
+                      photos_operation_svg_multiply,
+                      PHOTOS,
+                      OPERATION_SVG_MULTIPLY,
+                      GeglOperationPointComposer);
+
+G_END_DECLS
+
+#endif /* PHOTOS_OPERATION_SVG_MULTIPLY_H */