fix pattern position (yWorks#212)

src/nodes/pattern.ts

@@ -13,26 +13,30 @@ export class Pattern extends NonRenderedNode {
     }
 
     // the transformations directly at the node are written to the pattern transformation matrix
+    const x = context.svg2pdfParameters.x ?? 0
+    const y = context.svg2pdfParameters.y ?? 0
     const bBox = this.getBoundingBox(context)
-    const pattern = new TilingPattern(
-      [bBox[0], bBox[1], bBox[0] + bBox[2], bBox[1] + bBox[3]],
-      bBox[2],
-      bBox[3]
-    )
+    const startX = bBox[0] + x
+    const startY = bBox[1] + y
+    const width = bBox[2]
+    const height = bBox[3]
+    const endX = startX + width
+    const endY = startY + height
+    const pattern = new TilingPattern([startX, startY, endX, endY], width, height)
 
     context.pdf.beginTilingPattern(pattern)
     // continue without transformation
 
     for (const child of this.children) {
-      await child.render(
-        new Context(context.pdf, {
-          attributeState: context.attributeState,
-          refsHandler: context.refsHandler,
-          styleSheets: context.styleSheets,
-          viewport: context.viewport,
-          svg2pdfParameters: context.svg2pdfParameters
-        })
-      )
+      const childContext = new Context(context.pdf, {
+        attributeState: context.attributeState,
+        refsHandler: context.refsHandler,
+        styleSheets: context.styleSheets,
+        viewport: context.viewport,
+        svg2pdfParameters: context.svg2pdfParameters,
+        transform: context.pdf.Matrix(1, 0, 0, 1, x, y)
+      })
+      await child.render(childContext)
     }
     context.pdf.endTilingPattern(id, pattern)
   }