Attachment 112285 Details for Bug 88394 – Implement cairo function shading

[patch] Implement cairo function shading

0001-cairo-Implement-function-shading-using-mesh-gradient.patch (text/plain), 5.47 KB, created by Adrian Johnson on 2015-01-15 11:10:42 UTC

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Creator: Adrian Johnson

Created: 2015-01-15 11:10:42 UTC

Size: 5.47 KB

patch

obsolete

>From 6a1409364cd21a228f27861c38280a74f2096942 Mon Sep 17 00:00:00 2001
>From: Adrian Johnson <ajohnson@redneon.com>
>Date: Thu, 15 Jan 2015 21:20:05 +1030
>Subject: [PATCH] cairo: Implement function shading using mesh gradients
>
>Gfx draws function shadings by subdividing the shading until the
>colors are the same or the maximum subdivision is reached then fills
>each cell with the color of the mid point of the cell. The solid
>colors can result in a pixelated appearance.
>
>This patch implements a cairo specific version of the function shading
>that uses mesh gradients to draw each cell. By setting the corner of
>each patch to the shading color at that point, the mesh gradient will
>interpolate the colors resulting in a smooth appearance.
>
>Bug 88394
>---
> poppler/CairoOutputDev.cc | 101 ++++++++++++++++++++++++++++++++++++++++++++++
> poppler/CairoOutputDev.h  |   5 ++-
> 2 files changed, 105 insertions(+), 1 deletion(-)
>
>diff --git a/poppler/CairoOutputDev.cc b/poppler/CairoOutputDev.cc
>index 4e8abcf..a136105 100644
>--- a/poppler/CairoOutputDev.cc
>+++ b/poppler/CairoOutputDev.cc
>@@ -922,6 +922,107 @@ GBool CairoOutputDev::tilingPatternFill(GfxState *state, Gfx *gfxA, Catalog *cat
>   return gTrue;
> }
> 
>+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
>+GBool CairoOutputDev::functionShadedFill(GfxState *state, GfxFunctionShading *shading)
>+{
>+  // Function shaded fills are subdivided to rectangles that are the
>+  // following size in device space.  Note when printing this size is
>+  // in points.
>+  const int subdivide_pixels = 10;
>+
>+  double x_begin, x_end, x1, x2;
>+  double y_begin, y_end, y1, y2;
>+  double x_step;
>+  double y_step;
>+  GfxColor color;
>+  GfxRGB rgb;
>+  double *matrix;
>+  cairo_matrix_t mat;
>+
>+  matrix = shading->getMatrix();
>+  mat.xx = matrix[0];
>+  mat.yx = matrix[1];
>+  mat.xy = matrix[2];
>+  mat.yy = matrix[3];
>+  mat.x0 = matrix[4];
>+  mat.y0 = matrix[5];
>+  if (cairo_matrix_invert(&mat)) {
>+    error(errSyntaxWarning, -1, "matrix not invertible\n");
>+    return gFalse;
>+    }
>+
>+  // get cell size in pattern space
>+  x_step = y_step = subdivide_pixels;
>+  cairo_matrix_transform_distance (&mat, &x_step, &y_step);
>+
>+  cairo_pattern_destroy(fill_pattern);
>+  fill_pattern = cairo_pattern_create_mesh ();
>+  cairo_pattern_set_matrix(fill_pattern, &mat);
>+  shading->getDomain(&x_begin, &y_begin, &x_end, &y_end);
>+
>+  for (x1 = x_begin; x1 < x_end; x1 += x_step) {
>+    x2 = x1 + x_step;
>+    if (x2 > x_end)
>+      x2 = x_end;
>+
>+    for (y1 = y_begin; y1 < y_end; y1 += y_step) {
>+      y2 = y1 + y_step;
>+      if (y2 > y_end)
>+	y2 = y_end;
>+
>+      cairo_mesh_pattern_begin_patch (fill_pattern);
>+      cairo_mesh_pattern_move_to (fill_pattern, x1, y1);
>+      cairo_mesh_pattern_line_to (fill_pattern, x2, y1);
>+      cairo_mesh_pattern_line_to (fill_pattern, x2, y2);
>+      cairo_mesh_pattern_line_to (fill_pattern, x1, y2);
>+
>+      shading->getColor(x1, y1, &color);
>+      shading->getColorSpace()->getRGB(&color, &rgb);
>+      cairo_mesh_pattern_set_corner_color_rgb (fill_pattern, 0,
>+					       colToDbl(rgb.r),
>+					       colToDbl(rgb.g),
>+					       colToDbl(rgb.b));
>+
>+      shading->getColor(x2, y1, &color);
>+      shading->getColorSpace()->getRGB(&color, &rgb);
>+      cairo_mesh_pattern_set_corner_color_rgb (fill_pattern, 1,
>+					       colToDbl(rgb.r),
>+					       colToDbl(rgb.g),
>+					       colToDbl(rgb.b));
>+
>+      shading->getColor(x2, y2, &color);
>+      shading->getColorSpace()->getRGB(&color, &rgb);
>+      cairo_mesh_pattern_set_corner_color_rgb (fill_pattern, 2,
>+					       colToDbl(rgb.r),
>+					       colToDbl(rgb.g),
>+					       colToDbl(rgb.b));
>+
>+      shading->getColor(x1, y2, &color);
>+      shading->getColorSpace()->getRGB(&color, &rgb);
>+      cairo_mesh_pattern_set_corner_color_rgb (fill_pattern, 3,
>+					       colToDbl(rgb.r),
>+					       colToDbl(rgb.g),
>+					       colToDbl(rgb.b));
>+
>+      cairo_mesh_pattern_end_patch (fill_pattern);
>+    }
>+  }
>+
>+  double xMin, yMin, xMax, yMax;
>+  // get the clip region bbox
>+  state->getUserClipBBox(&xMin, &yMin, &xMax, &yMax);
>+  state->moveTo(xMin, yMin);
>+  state->lineTo(xMin, yMax);
>+  state->lineTo(xMax, yMax);
>+  state->lineTo(xMax, yMin);
>+  state->closePath();
>+  fill(state);
>+  state->clearPath();
>+
>+  return gTrue;
>+}
>+#endif /* CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0) */
>+
> GBool CairoOutputDev::axialShadedFill(GfxState *state, GfxAxialShading *shading, double tMin, double tMax) {
>   double x0, y0, x1, y1;
>   double dx, dy;
>diff --git a/poppler/CairoOutputDev.h b/poppler/CairoOutputDev.h
>index 8de391a..6b88e5a 100644
>--- a/poppler/CairoOutputDev.h
>+++ b/poppler/CairoOutputDev.h
>@@ -111,7 +111,7 @@ public:
> #if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
>   virtual GBool useShadedFills(int type) { return type <= 7; }
> #else
>-  virtual GBool useShadedFills(int type) { return type < 4; }
>+  virtual GBool useShadedFills(int type) { return type > 1 && type < 4; }
> #endif
> 
>   // Does this device use FillColorStop()?
>@@ -168,6 +168,9 @@ public:
> 				  double *mat, double *bbox,
> 				  int x0, int y0, int x1, int y1,
> 				  double xStep, double yStep);
>+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
>+  virtual GBool functionShadedFill(GfxState *state, GfxFunctionShading *shading);
>+#endif
>   virtual GBool axialShadedFill(GfxState *state, GfxAxialShading *shading, double tMin, double tMax);
>   virtual GBool axialShadedSupportExtend(GfxState *state, GfxAxialShading *shading);
>   virtual GBool radialShadedFill(GfxState *state, GfxRadialShading *shading, double sMin, double sMax);
>-- 
>2.1.4
>

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