From a91ebe4676fe7adca45ed5f90551f983776ccc3a Mon Sep 17 00:00:00 2001
From: Henning Stahlke <github@henningstahlke.de>
Date: Tue, 11 Dec 2018 23:38:29 +0100
Subject: [PATCH] canvas/svg.nas add optional basic support for linked images
 canvas/api.nas add alternative signature for ellipse and circle

---
 Nasal/canvas/api.nas | 14 ++++++++++----
 Nasal/canvas/svg.nas | 33 ++++++++++++++++++++++++++++++++-
 2 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/Nasal/canvas/api.nas b/Nasal/canvas/api.nas
index a00a9e6cf..6dcfc26b6 100644
--- a/Nasal/canvas/api.nas
+++ b/Nasal/canvas/api.nas
@@ -1005,11 +1005,17 @@ var Path = {
   #
   # @param rx    radius x
   # @param ry    radius y
-  # @param cx    (optional) center x coordinate
+  # @param cx    (optional) center x coordinate or vector [cx, cy]
   # @param cy    (optional) center y coordinate
   ellipse: func(rx, ry, cx = nil, cy = nil) {
-    cx = num(cx) or 0;
-    cy = num(cy) or 0;
+    if (typeof(cx) == "vector") {
+        cy = cx[1];
+        cx = cx[0];
+    }
+    else {
+        cx = num(cx) or 0;
+        cy = num(cy) or 0;
+    }
     me.moveTo(cx - rx, cy)
       .arcSmallCW(rx, ry, 0, 2*rx, 0)
       .arcSmallCW(rx, ry, 0, -2*rx, 0);
@@ -1020,7 +1026,7 @@ var Path = {
   # Add a circle to the path
   #
   # @param r     radius 
-  # @param cx    (optional) center x coordinate
+  # @param cx    (optional) center x coordinate or vector [cx, cy]
   # @param cy    (optional) center y coordinate
   circle: func(r, cx = nil, cy = nil) {
     return me.ellipse(r, r, cx, cy);
diff --git a/Nasal/canvas/svg.nas b/Nasal/canvas/svg.nas
index ca6e42696..e1914bbdd 100644
--- a/Nasal/canvas/svg.nas
+++ b/Nasal/canvas/svg.nas
@@ -3,6 +3,8 @@
 # @param group    The canvas.Group instance to append the parsed elements to
 # @param path     The path of the svg file (absolute or relative to FG_ROOT)
 # @param options  Optional hash of options
+#                 font-mapper  func
+#                 parse_images bool
 var parsesvg = func(group, path, options = nil)
 {
   if( !isa(group, Group) )
@@ -572,7 +574,7 @@ var parsesvg = func(group, path, options = nil)
       if( dash and size(dash) > 3 )
         # at least 2 comma separated values...
         stack[-1].setStrokeDashArray(split(',', dash));
-    }
+    } #end path/rect/ellipse/circle
     else if( name == "use" )
     {
       var ref = attr["xlink:href"];
@@ -595,6 +597,35 @@ var parsesvg = func(group, path, options = nil)
       append(defs_stack, "defs");
       return;
     }
+    else if (name == "image" and options["parse_images"])
+    {
+      var ref = attr["xlink:href"];
+      # ref must not be missing and shall not contain Windows path separator
+      # find("\\") is correct, backslash is control character and must be escaped
+      # by adding another backslash - otherwise parse error anywhere below 
+      if (ref == nil or find("\\", ref) > -1)
+      {
+        return printlog("info", "Invalid or missing href in image tag: '" ~ ref ~ "'");
+      }
+      if (substr(ref, 0, 5) == "data:") {
+        return printlog("info", "Unsupported embedded image");
+      }
+      elsif (substr(ref, 0, 5) != "file:") {
+        # absolute paths seem to start with "file:"
+        # prepend relative paths with the path of SVG file and hope the image is there
+        # file access limitations apply
+        ref = io.dirname(path) ~ ref;
+      }
+      pushElement("image", attr["id"]);
+
+      if (attr["x"] != nil and attr["y"] != nil) {
+        stack[-1].setTranslation(attr["x"], attr["y"]);
+      }
+      if (attr["width"] != nil and attr["height"] != nil) {
+        stack[-1].setSize(attr["width"], attr["height"]);
+      }
+      stack[-1].setFile(ref);
+    }
     else
     {
       printlog("info", "Skipping unknown element '" ~ name ~ "'");