Bugzilla#45822: Changed the dashed borders to appear more like dashes and less like dotted-borders

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1403643 13f79535-47bb-0310-9956-ffa450edef68

4 files changed, 45 insertions, 37 deletions

diff --git a/src/java/org/apache/fop/afp/AFPBorderPainter.java b/src/java/org/apache/fop/afp/AFPBorderPainter.java
index 42c58aa7d..06f1ecd11 100644
--- a/src/java/org/apache/fop/afp/AFPBorderPainter.java
+++ b/src/java/org/apache/fop/afp/AFPBorderPainter.java
@@ -22,6 +22,7 @@ package org.apache.fop.afp;
 import java.awt.geom.AffineTransform;
 
 import org.apache.fop.fo.Constants;
+import org.apache.fop.render.intermediate.BorderPainter;
 import org.apache.fop.util.ColorUtil;
 
 /**
@@ -126,24 +127,27 @@ public class AFPBorderPainter extends AbstractAFPPainter {
             }
             break;
         case Constants.EN_DASHED:
-            int thick = lineDataInfo.getThickness() * 3;
             if (borderPaintInfo.isHorizontal()) {
-                lineDataInfo.setX2 ( lineDataInfo.getX1() + thick );
+                int dashWidth = (int) (BorderPainter.dashWidthCalculator(x2 - x1, thickness));
+                lineDataInfo.setX2 ( lineDataInfo.getX1() + dashWidth );
                 lineDataInfo.setY2 ( lineDataInfo.getY1() );
                 int ex2 = Math.round(x2);
-                while (lineDataInfo.getX1() + thick < ex2) {
+                int spaceWidth = (int) (BorderPainter.DASHED_BORDER_SPACE_RATIO * dashWidth);
+                while (lineDataInfo.getX2() < ex2) {
                     dataStream.createLine(lineDataInfo);
-                    lineDataInfo.setX1 ( lineDataInfo.getX1() + 2 * thick );
-                    lineDataInfo.setX2 ( lineDataInfo.getX1() + thick );
+                    lineDataInfo.setX1 ( lineDataInfo.getX2() + spaceWidth );
+                    lineDataInfo.setX2 ( lineDataInfo.getX1() + dashWidth );
                 }
             } else {
+                int dashWidth = (int) BorderPainter.dashWidthCalculator(y2 - y1, thickness);
                 lineDataInfo.setX2 ( lineDataInfo.getX1() );
-                lineDataInfo.setY2 ( lineDataInfo.getY1() + thick );
+                lineDataInfo.setY2 ( lineDataInfo.getY1() + dashWidth );
                 int ey2 = Math.round(y2);
-                while (lineDataInfo.getY1() + thick < ey2) {
+                int spaceWidth = (int) (BorderPainter.DASHED_BORDER_SPACE_RATIO * dashWidth);
+                while (lineDataInfo.getY2() < ey2) {
                     dataStream.createLine(lineDataInfo);
-                    lineDataInfo.setY1 ( lineDataInfo.getY1() + 2 * thick );
-                    lineDataInfo.setY2 ( lineDataInfo.getY1() + thick );
+                    lineDataInfo.setY1 ( lineDataInfo.getY2() + spaceWidth );
+                    lineDataInfo.setY2 ( lineDataInfo.getY1() + dashWidth );
                 }
             }
             break;
diff --git a/src/java/org/apache/fop/render/intermediate/BorderPainter.java b/src/java/org/apache/fop/render/intermediate/BorderPainter.java
index 19e30b50f..d63c4534b 100644
--- a/src/java/org/apache/fop/render/intermediate/BorderPainter.java
+++ b/src/java/org/apache/fop/render/intermediate/BorderPainter.java
@@ -56,6 +56,11 @@ public class BorderPainter {
     /** Convention index of bottom-left border corners */
     protected static final int BOTTOM_LEFT = 3;
 
+    /** The ratio between a solid dash and the white-space in a dashed-border */
+    public static final float DASHED_BORDER_SPACE_RATIO = 0.5f;
+    /** The length of the dash as a factor of the border width i.e. 4 -> dashWidth = 4*borderWidth */
+    protected static final float DASHED_BORDER_LENGTH_FACTOR = 4.0f;
+
     private final GraphicsPainter graphicsPainter;
 
     public BorderPainter(GraphicsPainter graphicsPainter) {
@@ -274,6 +279,21 @@ public class BorderPainter {
         return bp != null && bp.isCollapseOuter();
     }
 
+    /**
+     * This method calculates the length of the "dash" in a dashed border. The dash satisfies the
+     * condition that corners start on a dash and end with a dash (rather than ending with a white space).
+     * @param borderLength The length of the border.
+     * @param borderWidth The width/thickness of the border.
+     * @param dashSpaceRatio The ratio between dashes and white-space.
+     * @return returns the length of the dash such that it fits the criteria above.
+     */
+    public static float dashWidthCalculator(float borderLength, float borderWidth) {
+        float dashWidth = DASHED_BORDER_LENGTH_FACTOR * borderWidth;
+        int period = (int) ((borderLength - dashWidth) / dashWidth / (1.0f + DASHED_BORDER_SPACE_RATIO));
+        period = period < 0 ? 0 : period;
+        return borderLength / (period * (1.0f + DASHED_BORDER_SPACE_RATIO) + 1.0f);
+    }
+
     /** TODO merge with drawRectangularBorders?
      * @param borderRect the border rectangle
      * @param bpsBefore the border specification on the before side
diff --git a/src/java/org/apache/fop/render/pdf/PDFGraphicsPainter.java b/src/java/org/apache/fop/render/pdf/PDFGraphicsPainter.java
index ff1ffb5ff..5e0792696 100644
--- a/src/java/org/apache/fop/render/pdf/PDFGraphicsPainter.java
+++ b/src/java/org/apache/fop/render/pdf/PDFGraphicsPainter.java
@@ -27,6 +27,7 @@ import java.io.IOException;
 import org.apache.fop.fo.Constants;
 import org.apache.fop.render.intermediate.ArcToBezierCurveTransformer;
 import org.apache.fop.render.intermediate.BezierCurvePainter;
+import org.apache.fop.render.intermediate.BorderPainter;
 import org.apache.fop.render.intermediate.GraphicsPainter;
 import org.apache.fop.traits.RuleStyle;
 import org.apache.fop.util.ColorUtil;
@@ -64,25 +65,15 @@ public class PDFGraphicsPainter implements GraphicsPainter, BezierCurvePainter {
         case Constants.EN_DASHED:
             generator.setColor(col);
             if (horz) {
-                float unit = Math.abs(2 * h);
-                int rep = (int) (w / unit);
-                if (rep % 2 == 0) {
-                    rep++;
-                }
-                unit = w / rep;
+                float dashedWidth = BorderPainter.dashWidthCalculator(w, h);
                 float ym = y1 + (h / 2);
-                generator.setDashLine(unit)
+                generator.setDashLine(dashedWidth, dashedWidth * BorderPainter.DASHED_BORDER_SPACE_RATIO)
                         .setLineWidth(h)
                         .strokeLine(x1, ym, x2, ym);
             } else {
-                float unit = Math.abs(2 * w);
-                int rep = (int) (h / unit);
-                if (rep % 2 == 0) {
-                    rep++;
-                }
-                unit = h / rep;
+                float dashedWidth = BorderPainter.dashWidthCalculator(h, w);
                 float xm = x1 + (w / 2);
-                generator.setDashLine(unit)
+                generator.setDashLine(dashedWidth, dashedWidth * BorderPainter.DASHED_BORDER_SPACE_RATIO)
                         .setLineWidth(w)
                         .strokeLine(xm, y1, xm, y2);
             }
diff --git a/src/java/org/apache/fop/render/ps/PSGraphicsPainter.java b/src/java/org/apache/fop/render/ps/PSGraphicsPainter.java
index ab766f701..9152d0937 100644
--- a/src/java/org/apache/fop/render/ps/PSGraphicsPainter.java
+++ b/src/java/org/apache/fop/render/ps/PSGraphicsPainter.java
@@ -31,6 +31,7 @@ import org.apache.xmlgraphics.ps.PSGenerator;
 import org.apache.fop.fo.Constants;
 import org.apache.fop.render.intermediate.ArcToBezierCurveTransformer;
 import org.apache.fop.render.intermediate.BezierCurvePainter;
+import org.apache.fop.render.intermediate.BorderPainter;
 import org.apache.fop.render.intermediate.GraphicsPainter;
 import org.apache.fop.traits.RuleStyle;
 import org.apache.fop.util.ColorUtil;
@@ -87,25 +88,17 @@ public class PSGraphicsPainter implements GraphicsPainter, BezierCurvePainter {
         case Constants.EN_DASHED:
             gen.useColor(col);
             if (horz) {
-                float unit = Math.abs(2 * h);
-                int rep = (int) (w / unit);
-                if (rep % 2 == 0) {
-                    rep++;
-                }
-                unit = w / rep;
-                gen.useDash("[" + unit + "] 0");
+                float dashWidth = BorderPainter.dashWidthCalculator(w, h);
+                gen.useDash("[" + dashWidth + " " + BorderPainter.DASHED_BORDER_SPACE_RATIO
+                        * dashWidth + "] 0");
                 gen.useLineCap(0);
                 gen.useLineWidth(h);
                 float ym = y1 + (h / 2);
                 drawLine(gen, x1, ym, x2, ym);
             } else {
-                float unit = Math.abs(2 * w);
-                int rep = (int) (h / unit);
-                if (rep % 2 == 0) {
-                    rep++;
-                }
-                unit = h / rep;
-                gen.useDash("[" + unit + "] 0");
+                float dashWidth = BorderPainter.dashWidthCalculator(h, w);
+                gen.useDash("[" + dashWidth + " " + BorderPainter.DASHED_BORDER_SPACE_RATIO
+                        * dashWidth + "] 0");
                 gen.useLineCap(0);
                 gen.useLineWidth(w);
                 float xm = x1 + (w / 2);