Merge pull request #2054 from scireum/feature/jvo/OX-9272-SVG-Charts

SVG Charts for PDFs (OX-9272)

pom.xml

@@ -17,8 +17,8 @@
     <url>https://www.sirius-lib.net</url>
 
     <properties>
-        <sirius.kernel>dev-43.1.0</sirius.kernel>
-        <sirius.web>dev-84.5.0</sirius.web>
+        <sirius.kernel>dev-43.2.1</sirius.kernel>
+        <sirius.web>dev-85.5.0</sirius.web>
         <sirius.db>dev-58.3.0</sirius.db>
     </properties>
 
@@ -160,5 +160,12 @@
             <artifactId>sevenzipjbinding-all-platforms</artifactId>
             <version>16.02-2.01</version>
         </dependency>
+
+        <!-- Used to render diagrams into SVG -->
+        <dependency>
+            <groupId>org.apache.xmlgraphics</groupId>
+            <artifactId>batik-all</artifactId>
+            <version>1.18</version>
+        </dependency>
     </dependencies>
 </project>

src/main/java/sirius/biz/charts/Chart.java

@@ -0,0 +1,181 @@
+/*
+ * Made with all the love in the world
+ * by scireum in Remshalden, Germany
+ *
+ * Copyright by scireum GmbH
+ * http://www.scireum.de - [email protected]
+ */
+
+package sirius.biz.charts;
+
+import org.apache.batik.anim.dom.SVGDOMImplementation;
+import org.w3c.dom.Element;
+
+import java.awt.Dimension;
+
+/**
+ * Provides an interface for charts that can be rendered as SVG.
+ */
+public abstract class Chart {
+
+    /**
+     * Contains the tag name for circle elements, {@value}.
+     */
+    protected static final String TAG_CIRCLE = "circle";
+
+    /**
+     * Contains the tag name for group elements, {@value}.
+     */
+    protected static final String TAG_GROUP = "g";
+
+    /**
+     * Contains the tag name for path elements, {@value}.
+     */
+    protected static final String TAG_PATH = "path";
+
+    /**
+     * Contains the tag name for SVG root elements, {@value}.
+     */
+    protected static final String TAG_SVG = "svg";
+
+    /**
+     * Contains the tag name for text elements, {@value}.
+     */
+    protected static final String TAG_TEXT = "text";
+
+    /**
+     * Contains the attribute name for the center x coordinate, {@value}.
+     */
+    protected static final String ATTRIBUTE_CENTER_X = "cx";
+
+    /**
+     * Contains the attribute name for the center y coordinate, {@value}.
+     */
+    protected static final String ATTRIBUTE_CENTER_Y = "cy";
+
+    /**
+     * Contains the attribute name for path definitions, {@value}.
+     */
+    protected static final String ATTRIBUTE_DEFINITION = "d";
+
+    /**
+     * Contains the attribute name for the fill colour, {@value}.
+     */
+    protected static final String ATTRIBUTE_FILL = "fill";
+
+    /**
+     * Contains the attribute name for the fill opacity, {@value}.
+     */
+    protected static final String ATTRIBUTE_FILL_OPACITY = "fill-opacity";
+
+    /**
+     * Contains the attribute name for the font size, {@value}.
+     */
+    protected static final String ATTRIBUTE_FONT_SIZE = "font-size";
+
+    /**
+     * Contains the attribute name for the radius, {@value}.
+     */
+    protected static final String ATTRIBUTE_RADIUS = "r";
+
+    /**
+     * Contains the attribute name for the stroke colour, {@value}.
+     */
+    protected static final String ATTRIBUTE_STROKE = "stroke";
+
+    /**
+     * Contains the attribute name for the stroke width, {@value}.
+     */
+    protected static final String ATTRIBUTE_STROKE_WIDTH = "stroke-width";
+
+    /**
+     * Contains the attribute name for the text anchor, {@value}.
+     */
+    protected static final String ATTRIBUTE_TEXT_ANCHOR = "text-anchor";
+
+    /**
+     * Contains the attribute name for the view box, {@value}.
+     */
+    protected static final String ATTRIBUTE_VIEW_BOX = "viewBox";
+
+    /**
+     * Contains the attribute name for the x coordinate, {@value}.
+     */
+    protected static final String ATTRIBUTE_X = "x";
+
+    /**
+     * Contains the attribute name for the y coordinate, {@value}.
+     */
+    protected static final String ATTRIBUTE_Y = "y";
+
+    /**
+     * Contains the value for the {@linkplain #ATTRIBUTE_FILL fill attribute} to avoid filling, {@value}.
+     */
+    protected static final String VALUE_FILL_NONE = "none";
+
+    /**
+     * Contains the value for the {@linkplain #ATTRIBUTE_TEXT_ANCHOR text anchor attribute} to align text at the start,
+     * {@value}.
+     */
+    protected static final String VALUE_TEXT_ANCHOR_START = "start";
+
+    /**
+     * Contains the value for the {@linkplain #ATTRIBUTE_TEXT_ANCHOR text anchor attribute} to align text centered,
+     * {@value}.
+     */
+    protected static final String VALUE_TEXT_ANCHOR_MIDDLE = "middle";
+
+    /**
+     * Contains the value for the {@linkplain #ATTRIBUTE_TEXT_ANCHOR text anchor attribute} to align text at the end,
+     * {@value}.
+     */
+    protected static final String VALUE_TEXT_ANCHOR_END = "end";
+
+    /**
+     * Contains the black colour as hex-string, {@value}. The value is used as primary colour for charts.
+     */
+    protected static final String COLOR_BLACK = "#000000";
+
+    /**
+     * Contains a dark gray colour as hex-string, {@value}. Its design system equivalent is {@code sirius-gray-dark}.
+     * <p>
+     * The value is used as secondary colour for charts.
+     */
+    protected static final String COLOR_GRAY_DARK = "#808080";
+
+    /**
+     * Contains the light gray colour as hex-string, {@value}. Its design system equivalent is {@code sirius-gray-light}.
+     * <p>
+     * The value is used as secondary colour for charts.
+     */
+    protected static final String COLOR_GRAY_LIGHT = "#c7c7c7";
+
+    /**
+     * Renders the chart as SVG.
+     *
+     * @param bounds the dimensions of the viewport
+     * @return the SVG representation of the chart
+     */
+    public abstract Element toSvg(Dimension bounds);
+
+    /**
+     * Creates an empty SVG element with the view box centered.
+     *
+     * @param bounds the dimensions of the viewport
+     * @return an empty SVG element with the view box centered
+     */
+    protected Element createSvgElementWithCenteredViewbox(Dimension bounds) {
+        Element svgElement = SVGDOMImplementation.getDOMImplementation()
+                                                 .createDocument(SVGDOMImplementation.SVG_NAMESPACE_URI,
+                                                                 Chart.TAG_SVG,
+                                                                 null)
+                                                 .getDocumentElement();
+        svgElement.setAttribute(Chart.ATTRIBUTE_VIEW_BOX,
+                                String.format("%f %f %f %f",
+                                              -0.5 * bounds.width,
+                                              -0.5 * bounds.height,
+                                              (double) bounds.width,
+                                              (double) bounds.height));
+        return svgElement;
+    }
+}

src/main/java/sirius/biz/charts/Charts.java

@@ -0,0 +1,46 @@
+/*
+ * Made with all the love in the world
+ * by scireum in Remshalden, Germany
+ *
+ * Copyright by scireum GmbH
+ * http://www.scireum.de - [email protected]
+ */
+
+package sirius.biz.charts;
+
+import com.lowagie.text.xml.XmlDomWriter;
+import org.w3c.dom.Element;
+import sirius.kernel.di.std.Register;
+import sirius.web.templates.pdf.TagliatellePDFContentHandler;
+
+import java.awt.Dimension;
+import java.io.StringWriter;
+
+/**
+ * Provides helpers to work with charts.
+ */
+@Register(classes = Charts.class)
+public class Charts {
+
+    /**
+     * Exports a chart as SVG string that is compatible with {@linkplain TagliatellePDFContentHandler PDF rendering}.
+     *
+     * @param chart  the chart to export
+     * @param bounds the dimensions of the viewport
+     * @return the SVG string representing the chart
+     */
+    public String exportChartForPdf(Chart chart, Dimension bounds) {
+        // we need to clean the SVG code a bit to make it compatible with the PDF renderer
+        Element element = chart.toSvg(bounds);
+        element.setAttribute("style",
+                             String.format("display: block; width: 100%%; height: %dmm; page-break-inside: avoid;",
+                                           bounds.height));
+
+        // note that the string writer uses a string buffer internally; no additional buffering or flushing is required
+        StringWriter writer = new StringWriter();
+        XmlDomWriter xmlWriter = new XmlDomWriter();
+        xmlWriter.setOutput(writer);
+        xmlWriter.write(element);
+        return writer.toString();
+    }
+}