FOP-2553: Support PDF shading to PS

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1724037 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/fop/render/ps/Gradient.java

@@ -0,0 +1,85 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.render.ps;
+
+import java.util.List;
+
+import org.apache.fop.render.gradient.Function;
+import org.apache.fop.render.gradient.Function.SubFunctionRenderer;
+import org.apache.fop.render.gradient.GradientMaker.DoubleFormatter;
+import org.apache.fop.render.gradient.Pattern;
+import org.apache.fop.render.gradient.Shading;
+
+/**
+ * Helper class to draw gradients in PostScript.
+ */
+public final class Gradient {
+
+    private Gradient() { }
+
+    public static String outputPattern(Pattern pattern, DoubleFormatter doubleFormatter) {
+        StringBuilder p = new StringBuilder(64);
+        p.append("/Pattern setcolorspace\n");
+        p.append("<< \n/Type /Pattern \n");
+
+        p.append("/PatternType " + pattern.getPatternType() + " \n");
+
+        if (pattern.getShading() != null) {
+            p.append("/Shading ");
+            outputShading(p, pattern.getShading(), doubleFormatter);
+            p.append(" \n");
+        }
+        p.append(">> \n");
+        List<Double> matrix = pattern.getMatrix();
+        if (matrix == null) {
+            p.append("matrix ");
+        } else {
+            p.append("[ ");
+            for (double m : pattern.getMatrix()) {
+                p.append(doubleFormatter.formatDouble(m));
+                p.append(" ");
+            }
+            p.append("] ");
+        }
+        p.append("makepattern setcolor\n");
+
+        return p.toString();
+    }
+
+    private static void outputShading(StringBuilder out, Shading shading, final DoubleFormatter doubleFormatter) {
+        final Function function = shading.getFunction();
+        Shading.FunctionRenderer functionRenderer = new Shading.FunctionRenderer() {
+
+            public void outputFunction(StringBuilder out) {
+                SubFunctionRenderer subFunctionRenderer = new Function.SubFunctionRenderer() {
+
+                    public void outputFunction(StringBuilder out, int functionIndex) {
+                        Function subFunction = function.getFunctions().get(functionIndex);
+                        assert subFunction.getFunctions().isEmpty();
+                        subFunction.output(out, doubleFormatter, null);
+                    }
+                };
+                function.output(out, doubleFormatter, subFunctionRenderer);
+            }
+        };
+        shading.output(out, doubleFormatter, functionRenderer);
+    }
+
+}