Fixing out of bounds exception when there is an artifical key frame for the first fraction and for the last fraction at the same time. Fixed by using the same approach as if there was only an artificial key frame for the last fraction, which reuses the alpha of the last color.

Adjustment for the starting alpha of an artificial key frame for the first fraction. Gradients should only be visible between two stop elements, not between start and stop or stop and end. To achieve this, the alpha needs to be the same for start and first stop.

Author: ganomi

graphics2d/src/main/java/de/rototor/pdfbox/graphics2d/PdfBoxGraphics2DPaintApplier.java

@@ -1305,23 +1305,28 @@ private int patchFunction(int colorIdx, COSDictionary cosBase)
                 final float alpha1;
                 if (needBoundsKeyFrameEntry(fractions))
                 {
+                    PdfBoxGraphics2DColor clr;
                     if (0 == colorIdx)
                     {
-                        alpha0 = 1f;
+                        // Use first colors alpha for the inserted keyframe instead of 1f.
+                        // Gradients should only happen between explicitly defined stops.
+                        clr = alphaGrayscaleColors[0];
+                        alpha0 = clr.toPDColor().getComponents()[0];
                     }
                     else
                     {
-                        PdfBoxGraphics2DColor clr = alphaGrayscaleColors[colorIdx - 1];
+                        clr = alphaGrayscaleColors[colorIdx - 1];
                         alpha0 = clr.toPDColor().getComponents()[0];
                     }
-
-                    PdfBoxGraphics2DColor clr = alphaGrayscaleColors[colorIdx];
+                    // In case we have an inserted exit keyframe in addition to an inserted entry keyframe,
+                    // we are already out of colors and will reuse the last color's alpha value.
+                    if (colorIdx < alphaGrayscaleColors.length)
+                        clr = alphaGrayscaleColors[colorIdx];
                     alpha1 = clr.toPDColor().getComponents()[0];
                     colorIdx++;
                 }
                 else
                 {
-
                     PdfBoxGraphics2DColor clr = alphaGrayscaleColors[colorIdx];
                     alpha0 = clr.toPDColor().getComponents()[0];
                     if (colorIdx + 1 < alphaGrayscaleColors.length)

graphics2d/src/test/java/de/rototor/pdfbox/graphics2d/RenderSVGsTest.java

@@ -33,6 +33,7 @@ public void testSVGs() throws IOException
         renderSVG("focalpoint_radial_sample.svg", 100);
         renderSVG("tux_colored.svg", 0.3);
         renderSVG("tux.svg", 0.3);
+        renderSVG("gradients.svg", 0.3);
         renderSVG("barChart.svg", 0.45);
         renderSVG("gump-bench.svg", 1);
         renderSVG("json.svg", 150);