Merge pull request #36 from guzba/master

svg circle

src/pixie/fileformats/svg.nim

@@ -78,12 +78,14 @@ proc draw(
     discard
   of "desc":
     discard
+
   of "g":
     let ctx = decodeCtx(ctxStack[^1], node)
     ctxStack.add(ctx)
     for child in node:
       img.draw(child, ctxStack)
     discard ctxStack.pop()
+
   of "path":
     let
       d = node.attr("d")
@@ -91,11 +93,12 @@ proc draw(
     if ctx.fill != ColorRGBA():
       let (bounds, fillImg) = fillPathBounds(d, ctx.fill, ctx.transform)
       img.draw(fillImg, bounds.xy)
-    if ctx.stroke != ColorRGBA():
+    if ctx.stroke != ColorRGBA() and ctx.strokeWidth > 0:
       let (bounds, strokeImg) = strokePathBounds(
         d, ctx.stroke, ctx.strokeWidth, ctx.transform
       )
       img.draw(strokeImg, bounds.xy)
+
   of "rect":
     let
       ctx = decodeCtx(ctxStack[^1], node)
@@ -111,8 +114,35 @@ proc draw(
     path.closePath()
     if ctx.fill != ColorRGBA():
       img.fillPath(path, ctx.fill, ctx.transform)
-    if ctx.stroke != ColorRGBA():
+    if ctx.stroke != ColorRGBA() and ctx.strokeWidth > 0:
       img.strokePath(path, ctx.stroke, ctx.strokeWidth, ctx.transform)
+
+  of "circle":
+    # Reference for magic constant:
+    # https://dl3.pushbulletusercontent.com/a3fLVC8boTzRoxevD1OgCzRzERB9z2EZ/unknown.png
+    let
+      ctx = decodeCtx(ctxStack[^1], node)
+      cx = parseFloat(node.attr("cx"))
+      cy = parseFloat(node.attr("cy"))
+      r = parseFloat(node.attr("r"))
+      magic = (4.0 * (-1.0 + sqrt(2.0)) / 3) * r
+      path = newPath()
+    path.moveTo(cx + r, cy)
+    path.bezierCurveTo(cx + r, cy + magic, cx + magic, cy + r, cx, cy + r)
+    path.bezierCurveTo(cx - magic, cy + r, cx - r, cy + magic, cx - r, cy)
+    path.bezierCurveTo(cx - r, cy - magic, cx - magic, cy - r, cx, cy - r)
+    path.bezierCurveTo(cx + magic, cy - r, cx + r, cy - magic, cx + r, cy)
+    path.closePath()
+    let d = $path
+    if ctx.fill != ColorRGBA():
+      let (bounds, fillImg) = fillPathBounds(d, ctx.fill, ctx.transform)
+      img.draw(fillImg, bounds.xy)
+    if ctx.stroke != ColorRGBA() and ctx.strokeWidth > 0:
+      let (bounds, strokeImg) = strokePathBounds(
+        d, ctx.stroke, ctx.strokeWidth, ctx.transform
+      )
+      img.draw(strokeImg, bounds.xy)
+
   else:
     raise newException(PixieError, "Unsupported SVG tag: " & node.tag & ".")
 

src/pixie/paths.nim

@@ -833,9 +833,11 @@ proc lineTo*(path: Path, x, y: float32) =
   path.commands.add PathCommand(kind: Line, numbers: @[x, y])
   path.at = vec2(x, y)
 
-proc bezierCurveTo*(path: Path) =
+proc bezierCurveTo*(path: Path, x1, y1, x2, y2, x3, y3: float32) =
   ## Adds a cubic Bézier curve to the path. It requires three points. The first two points are control points and the third one is the end point. The starting point is the last point in the current path, which can be changed using moveTo() before creating the Bézier curve.
-  raise newException(ValueError, "not implemented")
+  path.commands.add(PathCommand(kind: Cubic, numbers: @[
+    x1, y1, x2, y2, x3, y3
+  ]))
 
 proc quadraticCurveTo*(path: Path) =
   ## Adds a quadratic Bézier curve to the current path.

tests/images/svg/quad01.svg

@@ -0,0 +1,28 @@
+<?xml version="1.0" standalone="no"?>
+<svg width="12cm" height="6cm" viewBox="0 0 1200 600"
+     xmlns="http://www.w3.org/2000/svg" version="1.1">
+  <title>Example quad01 - quadratic Bézier commands in path data</title>
+  <desc>Picture showing a "Q" a "T" command,
+        along with annotations showing the control points
+        and end points</desc>
+  <rect x="1" y="1" width="1198" height="598"
+        fill="none" stroke="blue" stroke-width="1" />
+
+  <path d="M200,300 Q400,50 600,300 T1000,300"
+        fill="none" stroke="red" stroke-width="5"  />
+  <!-- End points -->
+  <g fill="black" >
+    <circle cx="200" cy="300" r="10"/>
+    <circle cx="600" cy="300" r="10"/>
+    <circle cx="1000" cy="300" r="10"/>
+  </g>
+  <!-- Control points and lines from end points to control points -->
+  <g fill="#888888" >
+    <circle cx="400" cy="50" r="10"/>
+    <circle cx="800" cy="550" r="10"/>
+  </g>
+  <path d="M200,300 L400,50 L600,300 
+           L800,550 L1000,300"
+        fill="none" stroke="#888888" stroke-width="2" />
+</svg>
+

tests/test_svg.nim

@@ -2,6 +2,7 @@ import pixie/fileformats/svg, pixie, strformat
 
 const files = [
   "triangle01",
+  "quad01",
   "Ghostscript_Tiger"
 ]