re-add Grayscale color mode

Fixed bugs:
  - https://launchpad.net/bugs/885048

(bzr r11953)

3 files changed, 79 insertions, 41 deletions

diff --git a/src/display/drawing.cpp b/src/display/drawing.cpp
index 77f24caf3..171cc014f 100644
--- a/src/display/drawing.cpp
+++ b/src/display/drawing.cpp
@@ -4,8 +4,9 @@
  *//*
  * Authors:
  *   Krzysztof Kosiński <tweenk.pl@gmail.com>
+ *   Johan Engelen <j.b.c.engelen@alumnus.utwente.nl>
  *
- * Copyright (C) 2011 Authors
+ * Copyright (C) 2011-2012 Authors
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
@@ -14,6 +15,12 @@
 #include "nr-filter-gaussian.h"
 #include "nr-filter-types.h"
 
+//grayscale colormode:
+#include "nr-filter-colormatrix.h"
+#include "cairo-templates.h"
+#include "drawing-context.h"
+
+
 namespace Inkscape {
 
 Drawing::Drawing(SPCanvasArena *arena)
@@ -145,12 +152,37 @@ Drawing::update(Geom::IntRect const &area, UpdateContext const &ctx, unsigned fl
     _pickItemsForCaching();
 }
 
+// hardcoded grayscale color matrix values. could be turned into preference settings in future.
+static const gdouble grayscale_value_matrix[] = {
+    0.21, 0.72, 0.072, 0, 0,
+    0.21, 0.72, 0.072, 0, 0,
+    0.21, 0.72, 0.072, 0, 0,
+    0   , 0   , 0    , 1, 0
+};
+static Filters::FilterColorMatrix::ColorMatrixMatrix grayscale_colormatrix(
+    std::vector<gdouble> (grayscale_value_matrix, grayscale_value_matrix + sizeof(grayscale_value_matrix) / sizeof(grayscale_value_matrix[0]) )
+);
+
 void
 Drawing::render(DrawingContext &ct, Geom::IntRect const &area, unsigned flags)
 {
     if (_root) {
         _root->render(ct, area, flags);
     }
+
+    if (colorMode() == COLORMODE_GRAYSCALE) {
+        // apply grayscale filter on top of everything
+        cairo_surface_t *input = ct.rawTarget();
+        cairo_surface_t *out = ink_cairo_surface_create_identical(input);
+        ink_cairo_surface_filter(input, out, grayscale_colormatrix);
+        Geom::Point origin = ct.targetLogicalBounds().min();
+        ct.setSource(out, origin[Geom::X], origin[Geom::Y]);
+        ct.setOperator(CAIRO_OPERATOR_SOURCE);
+        ct.paint();
+        ct.setOperator(CAIRO_OPERATOR_OVER);
+    
+        cairo_surface_destroy(out);
+    }
 }
 
 DrawingItem *
diff --git a/src/display/nr-filter-colormatrix.cpp b/src/display/nr-filter-colormatrix.cpp
index 33718ed68..fad6215ff 100644
--- a/src/display/nr-filter-colormatrix.cpp
+++ b/src/display/nr-filter-colormatrix.cpp
@@ -32,50 +32,47 @@ FilterPrimitive * FilterColorMatrix::create() {
 FilterColorMatrix::~FilterColorMatrix()
 {}
 
-struct ColorMatrixMatrix {
-    ColorMatrixMatrix(std::vector<double> const &values) {
-        unsigned limit = std::min(static_cast<size_t>(20), values.size());
-        for (unsigned i = 0; i < limit; ++i) {
-            if (i % 5 == 4) {
-                _v[i] = round(values[i]*255*255);
-            } else {
-                _v[i] = round(values[i]*255);
-            }
-        }
-        for (unsigned i = limit; i < 20; ++i) {
-            _v[i] = 0;
+FilterColorMatrix::ColorMatrixMatrix::ColorMatrixMatrix(std::vector<double> const &values) {
+    unsigned limit = std::min(static_cast<size_t>(20), values.size());
+    for (unsigned i = 0; i < limit; ++i) {
+        if (i % 5 == 4) {
+            _v[i] = round(values[i]*255*255);
+        } else {
+            _v[i] = round(values[i]*255);
         }
     }
+    for (unsigned i = limit; i < 20; ++i) {
+        _v[i] = 0;
+    }
+}
 
-    guint32 operator()(guint32 in) {
-        EXTRACT_ARGB32(in, a, r, g, b)
-        // we need to un-premultiply alpha values for this type of matrix
-        // TODO: unpremul can be ignored if there is an identity mapping on the alpha channel
-        if (a != 0) {
-            r = unpremul_alpha(r, a);
-            g = unpremul_alpha(g, a);
-            b = unpremul_alpha(b, a);
-        }
-
-        gint32 ro = r*_v[0]  + g*_v[1]  + b*_v[2]  + a*_v[3]  + _v[4];
-        gint32 go = r*_v[5]  + g*_v[6]  + b*_v[7]  + a*_v[8]  + _v[9];
-        gint32 bo = r*_v[10] + g*_v[11] + b*_v[12] + a*_v[13] + _v[14];
-        gint32 ao = r*_v[15] + g*_v[16] + b*_v[17] + a*_v[18] + _v[19];
-        ro = (pxclamp(ro, 0, 255*255) + 127) / 255;
-        go = (pxclamp(go, 0, 255*255) + 127) / 255;
-        bo = (pxclamp(bo, 0, 255*255) + 127) / 255;
-        ao = (pxclamp(ao, 0, 255*255) + 127) / 255;
+guint32 FilterColorMatrix::ColorMatrixMatrix::operator()(guint32 in) {
+    EXTRACT_ARGB32(in, a, r, g, b)
+    // we need to un-premultiply alpha values for this type of matrix
+    // TODO: unpremul can be ignored if there is an identity mapping on the alpha channel
+    if (a != 0) {
+        r = unpremul_alpha(r, a);
+        g = unpremul_alpha(g, a);
+        b = unpremul_alpha(b, a);
+    }
 
-        ro = premul_alpha(ro, ao);
-        go = premul_alpha(go, ao);
-        bo = premul_alpha(bo, ao);
+    gint32 ro = r*_v[0]  + g*_v[1]  + b*_v[2]  + a*_v[3]  + _v[4];
+    gint32 go = r*_v[5]  + g*_v[6]  + b*_v[7]  + a*_v[8]  + _v[9];
+    gint32 bo = r*_v[10] + g*_v[11] + b*_v[12] + a*_v[13] + _v[14];
+    gint32 ao = r*_v[15] + g*_v[16] + b*_v[17] + a*_v[18] + _v[19];
+    ro = (pxclamp(ro, 0, 255*255) + 127) / 255;
+    go = (pxclamp(go, 0, 255*255) + 127) / 255;
+    bo = (pxclamp(bo, 0, 255*255) + 127) / 255;
+    ao = (pxclamp(ao, 0, 255*255) + 127) / 255;
+
+    ro = premul_alpha(ro, ao);
+    go = premul_alpha(go, ao);
+    bo = premul_alpha(bo, ao);
+
+    ASSEMBLE_ARGB32(pxout, ao, ro, go, bo)
+    return pxout;
+}
 
-        ASSEMBLE_ARGB32(pxout, ao, ro, go, bo)
-        return pxout;
-    }
-private:
-    gint32 _v[20];
-};
 
 struct ColorMatrixSaturate {
     ColorMatrixSaturate(double v_in) {
@@ -163,7 +160,7 @@ void FilterColorMatrix::render_cairo(FilterSlot &slot)
 
     switch (type) {
     case COLORMATRIX_MATRIX:
-        ink_cairo_surface_filter(input, out, ColorMatrixMatrix(values));
+        ink_cairo_surface_filter(input, out, FilterColorMatrix::ColorMatrixMatrix(values));
         break;
     case COLORMATRIX_SATURATE:
         ink_cairo_surface_filter(input, out, ColorMatrixSaturate(value));
diff --git a/src/display/nr-filter-colormatrix.h b/src/display/nr-filter-colormatrix.h
index 5f21a4210..c7e5e91d9 100644
--- a/src/display/nr-filter-colormatrix.h
+++ b/src/display/nr-filter-colormatrix.h
@@ -42,6 +42,15 @@ public:
     virtual void set_type(FilterColorMatrixType type);
     virtual void set_value(gdouble value);
     virtual void set_values(std::vector<gdouble> const &values);
+
+public:
+    struct ColorMatrixMatrix {
+        ColorMatrixMatrix(std::vector<double> const &values);
+        guint32 operator()(guint32 in);
+    private:
+        gint32 _v[20];
+    };
+
 private:
     std::vector<gdouble> values;
     gdouble value;