fixes bug if invalid arc radii are used

src/main/java/de/neemann/digital/draw/graphics/PolygonParser.java

@@ -255,6 +255,20 @@ public class PolygonParser {
      */
     //CHECKSTYLE.OFF: ParameterNumberCheck
     private void addArc(Polygon p, VectorInterface current, float rx, float ry, float rot, boolean large, boolean sweep, VectorFloat pos) {
+
+        // if rx=0 or ry=0 add a straight line
+        if (rx == 0 || ry == 0) {
+            p.add(pos);
+            return;
+        }
+
+        // take the absolute value of rx, ry
+        if (rx < 0)
+            rx = -rx;
+        if (ry < 0)
+            ry = -ry;
+
+        // transform the ellipse to a circle
         Transform tr = Transform.IDENTITY;
         if (rx != ry)
             tr = TransformMatrix.scale(1, rx / ry);
@@ -270,6 +284,11 @@ public class PolygonParser {
         // ellipse is transformed to a circle with radius r
         float r = rx;
 
+        // correct invalid radii
+        final float dist = p1.sub(p2).len();
+        if (dist > r * 2)
+            r = dist / 2;
+
         double x1 = p1.getXFloat();
         double y1 = p1.getYFloat();
         double x2 = p2.getXFloat();
@@ -281,6 +300,7 @@ public class PolygonParser {
         double y2q = y2 * y2;
         double rq = r * r;
 
+        try {
             double x0A = (r * (y1 - y2) * sqrt(rq * (4 * rq - y1q + y2 * (2 * y1 - y2)) - rq * (x1q - 2 * x1 * x2 + x2q)) * sign(x1 - x2) + r * (x1 + x2) * sqrt(rq * (y1q - 2 * y1 * y2 + y2q) + rq * (x1q - 2 * x1 * x2 + x2q))) / (2 * r * sqrt(rq * (y1q - 2 * y1 * y2 + y2q) + rq * (x1q - 2 * x1 * x2 + x2q)));
             double y0A = (r * (y1 + y2) * sqrt(rq * (y1q - 2 * y1 * y2 + y2q) + rq * (x1q - 2 * x1 * x2 + x2q)) - r * sqrt(rq * (4 * rq - y1q + y2 * (2 * y1 - y2)) - rq * (x1q - 2 * x1 * x2 + x2q)) * abs(x1 - x2)) / (2 * r * sqrt(rq * (y1q - 2 * y1 * y2 + y2q) + rq * (x1q - 2 * x1 * x2 + x2q)));
             double x0B = (r * (x1 + x2) * sqrt(rq * (y1q - 2 * y1 * y2 + y2q) + rq * (x1q - 2 * x1 * x2 + x2q)) - r * (y1 - y2) * sqrt(rq * (4 * rq - y1q + y2 * (2 * y1 - y2)) - rq * (x1q - 2 * x1 * x2 + x2q)) * sign(x1 - x2)) / (2 * r * sqrt(rq * (y1q - 2 * y1 * y2 + y2q) + rq * (x1q - 2 * x1 * x2 + x2q)));
@@ -325,6 +345,10 @@ public class PolygonParser {
                 start += delta;
             }
             addArcPoint(p, lastStart, end, x0, y0, r, invert);
+
+        } catch (SqrtException e) {
+            p.add(pos);
+        }
     }
     //CHECKSTYLE.ON: ParameterNumberCheck
 
@@ -336,8 +360,13 @@ public class PolygonParser {
         p.add(c.transform(tr), p1.transform(tr));
     }
 
-    private static double sqrt(double x) {
+    private static double sqrt(double x) throws SqrtException {
+        if (x > 0)
             return Math.sqrt(x);
+        if (x > -1e-6)
+            return 0;
+
+        throw new SqrtException();
     }
 
     private static double sign(double x) {
@@ -394,4 +423,6 @@ public class PolygonParser {
         return p;
     }
 
+    private static class SqrtException extends Exception {
+    }
 }

src/main/java/de/neemann/digital/draw/shapes/custom/svg/Context.java

@@ -42,6 +42,7 @@ class Context {
         tr = Transform.IDENTITY;
         thickness = 1;
         color = Color.BLACK;
+        fill = Color.BLACK;
     }
 
     private Context(Context parent) {
@@ -50,6 +51,7 @@ class Context {
         color = parent.color;
         thickness = parent.thickness;
         fontSize = parent.fontSize;
+        textAnchor = parent.textAnchor;
         fillRuleEvenOdd = parent.fillRuleEvenOdd;
     }
 
@@ -128,7 +130,6 @@ class Context {
         return fontSize;
     }
 
-
     private interface AttrParser {
         void parse(Context c, String value) throws SvgException;
     }

src/main/java/de/neemann/digital/draw/shapes/custom/svg/SvgImporter.java

@@ -135,7 +135,7 @@ public class SvgImporter {
     }
 
     private void drawPolygon(CustomShapeDescription csd, Context c, Polygon polygon) {
-        if (c.getFilled() != null)
+        if (c.getFilled() != null && polygon.isClosed())
             csd.addPolygon(polygon.transform(c.getTransform()), c.getThickness(), c.getFilled(), true);
         if (c.getColor() != null)
             csd.addPolygon(polygon.transform(c.getTransform()), c.getThickness(), c.getColor(), false);
@@ -184,10 +184,7 @@ public class SvgImporter {
                     .add(c.v(x + width, y + height))
                     .add(c.v(x, y + height));
 
-        if (c.getFilled() != null)
+        drawPolygon(csd, c, polygon);
-            csd.addPolygon(polygon, c.getThickness(), c.getFilled(), true);
-        if (c.getColor() != null)
-            csd.addPolygon(polygon, c.getThickness(), c.getColor(), false);
     }
 
     private void drawCircle(CustomShapeDescription csd, Element element, Context c) {
@@ -229,10 +226,7 @@ public class SvgImporter {
                     .add(c.v(x + rx, y - cy), c.v(x + cx, y - ry), c.v(x, y - ry))
                     .add(c.v(x - cx, y - ry), c.v(x - rx, y - cy), c.v(x - rx, y));
 
-            if (c.getFilled() != null)
+            drawPolygon(csd, c, poly);
-                csd.addPolygon(poly, c.getThickness(), c.getFilled(), true);
-            if (c.getColor() != null)
-                csd.addPolygon(poly, c.getThickness(), c.getColor(), false);
         }
     }
 

src/test/java/de/neemann/digital/draw/shapes/custom/SvgImporterTest.java

@@ -278,6 +278,18 @@ public class SvgImporterTest extends TestCase {
                 .check();
     }
 
+    public void testInvalidArcRadii() throws IOException, SvgException, PolygonParser.ParserException, PinException {
+        CustomShapeDescription custom = new SvgImporter(
+                in("<svg viewBox=\"0 0 200 100\" xmlns=\"http://www.w3.org/2000/svg\">\n" +
+                        "<path fill=\"none\" stroke=\"black\" stroke-width=\"3\"\n" +
+                        "      d=\"M 0,0 L 40,0 A 10,20,0,1,1,100,0 L 140,0\"/>\n" +
+                        "</svg>")).create();
+
+        new CSDChecker(custom)
+                .checkPolygon("M 0,0 L 40,0 Q 40,-16.076952 44.019238,-30 Q 48.038475,-43.92305 55,-51.961525 Q 61.961525,-60 70,-60 Q 78.038475,-60 85,-51.961525 Q 91.961525,-43.92305 95.98076,-30 Q 100,-16.076952 100,-1.469576E-14 L 140,0")
+                .check();
+    }
+
     public void testInkscape1() throws IOException, SvgException, PolygonParser.ParserException, PinException {
         CustomShapeDescription custom = new SvgImporter(
                 in("<svg viewBox=\"0 0 200 100\" xmlns=\"http://www.w3.org/2000/svg\">\n" +
@@ -429,7 +441,7 @@ public class SvgImporterTest extends TestCase {
             ArrayList<VectorInterface> isPoints = new ArrayList<>();
             polygon.traverse(isPoints::add);
 
-            //System.out.println(polygon);
+            System.out.println(polygon);
 
             assertEquals("not the correct polygon size", shouldPoints.size(), isPoints.size());
             for (int i = 0; i < shouldPoints.size(); i++) {