1 files changed, 92 insertions, 0 deletions
diff --git a/src/java/org/apache/fop/render/extensions/prepress/PageScale.java b/src/java/org/apache/fop/render/extensions/prepress/PageScale.java
new file mode 100644
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+++ b/src/java/org/apache/fop/render/extensions/prepress/PageScale.java
@@ -0,0 +1,92 @@
+/*
+ * 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.extensions.prepress;
+
+import java.awt.geom.Point2D;
+import java.text.MessageFormat;
+import java.util.regex.Pattern;
+
+import org.apache.xmlgraphics.util.QName;
+
+import org.apache.fop.fo.extensions.ExtensionElementMapping;
+
+/**
+ * This class provides utility methods to parse the 'fox:scale' extension attribute.
+ */
+public final class PageScale {
+
+    /**
+     * The extension 'scale' attribute for the simple-page-master element.
+     */
+    public static final QName EXT_PAGE_SCALE
+            = new QName(ExtensionElementMapping.URI, null, "scale");
+
+    private static final Pattern WHITESPACE_PATTERN = Pattern.compile("\\s+");
+
+    /**
+     * Utility classes should not have a public or default constructor
+     */
+    private PageScale() {
+    }
+
+    /**
+     * Compute scale parameters from given fox:scale attribute which has the format: scaleX [scaleY]
+     * If scaleY is not defined, it equals scaleX.
+     * @param scale scale attribute, input format: scaleX [scaleY]
+     * @return the pair of (sx, sy) values
+     */
+    public static Point2D getScale(String scale) {
+        // TODO throw appropriate exceptions that can be caught by the event
+        // notification mechanism
+        final String err = "Extension 'scale' attribute has incorrect value(s): {0}";
+
+        if (scale == null || scale.equals("")) {
+            return null;
+        }
+
+        String[] scales = WHITESPACE_PATTERN.split(scale);
+        double scaleX;
+        try {
+            scaleX = Double.parseDouble(scales[0]);
+        } catch (NumberFormatException nfe) {
+            throw new IllegalArgumentException(MessageFormat.format(err, new Object[]{scale}));
+        }
+        double scaleY;
+        switch (scales.length) {
+        case 1:
+            scaleY = scaleX;
+            break;
+        case 2:
+            try {
+                scaleY = Double.parseDouble(scales[1]);
+            } catch (NumberFormatException nfe) {
+                throw new IllegalArgumentException(MessageFormat.format(err, new Object[]{scale}));
+            }
+            break;
+        default:
+            throw new IllegalArgumentException("Too many arguments");
+        }
+        if (scaleX <= 0 || scaleY <= 0) {
+            throw new IllegalArgumentException(MessageFormat.format(err, new Object[]{scale}));
+        }
+
+        return new Point2D.Double(scaleX, scaleY);
+    }
+}