Fix pattern rendering and some xform bugs

svg-flatten/include/geom2d.hpp

@@ -67,8 +67,8 @@ namespace gerbolyze {
             }
 
             xform2d &translate(double x, double y) {
-                x0 += x;
-                y0 += y;
+                x0 += x*xx + y*xy;
+                y0 += y*yy + x*yx;
                 return *this;
             }
 
@@ -109,7 +109,7 @@ namespace gerbolyze {
             d2p doc2phys(const d2p p) {
                 return d2p {
                     xx * p[0] + xy * p[1] + x0,
-                    xy * p[1] + yy * p[1] + y0
+                    yx * p[0] + yy * p[1] + y0
                 };
             }
 

svg-flatten/src/svg_doc.cpp

@@ -152,8 +152,8 @@ void gerbolyze::SVGDocument::export_svg_group(xform2d &mat, const RenderSettings
 
     } else {
         clip_path = *lookup;
+        local_xf.transform_paths(clip_path);
     }
-    local_xf.transform_paths(clip_path);
 
     /* Clip against parent's clip path (both are now in document coordinates) */
     if (!parent_clip_path.empty()) {
@@ -251,9 +251,10 @@ void gerbolyze::SVGDocument::export_svg_path(xform2d &mat, const RenderSettings
             c.AddPaths(fill_paths, ptSubject, /* closed */ true);
             c.AddPaths(clip_path, ptClip, /* closed */ true);
             c.StrictlySimple(true);
+
             /* fill rules are nonzero since both subject and clip have already been normalized by clipper. */ 
-            c.Execute(ctIntersection, ptree, pftNonZero, pftNonZero);
-            PolyTreeToPaths(ptree, fill_paths);
+            c.Execute(ctIntersection, ptree_fill, pftNonZero, pftNonZero);
+            PolyTreeToPaths(ptree_fill, fill_paths);
         }
 
         /* Call out to pattern tiler for pattern fills. The path becomes the clip here. */

svg-flatten/src/svg_pattern.cpp

@@ -59,10 +59,10 @@ void gerbolyze::Pattern::tile (xform2d &mat, const gerbolyze::RenderSettings &rs
 
     /* Transform x, y, w, h from pattern coordinate space into parent coordinates by applying the inverse
      * patternTransform. This is necessary so we iterate over the correct bounds when tiling below */
-    d2p pos_xf = patternTransform_inv.doc2phys(d2p{x, y});
+    d2p pos_xf = mat.doc2phys(d2p{x, y});
     double inst_x = pos_xf[0], inst_y = pos_xf[1];
-    double inst_w = patternTransform_inv.doc2phys_dist(w);
-    double inst_h = patternTransform_inv.doc2phys_dist(h);
+    double inst_w = mat.doc2phys_dist(w);
+    double inst_h = mat.doc2phys_dist(h);
 
     ClipperLib::IntRect clip_bounds = get_paths_bounds(clip);
     double bx = clip_bounds.left / clipper_scale;
@@ -70,6 +70,14 @@ void gerbolyze::Pattern::tile (xform2d &mat, const gerbolyze::RenderSettings &rs
     double bw = (clip_bounds.right - clip_bounds.left) / clipper_scale;
     double bh = (clip_bounds.bottom - clip_bounds.top) / clipper_scale;
 
+    d2p clip_p0 = patternTransform_inv.doc2phys(d2p{bx, by});
+    d2p clip_p1 = patternTransform_inv.doc2phys(d2p{bx+bw, by+bh});
+
+    bx = fmin(clip_p0[0], clip_p1[0]);
+    by = fmin(clip_p0[1], clip_p1[1]);
+    bw = fmax(clip_p0[0], clip_p1[0]) - bx;
+    bh = fmax(clip_p0[1], clip_p1[1]) - by;
+
     if (patternUnits == SVG_ObjectBoundingBox) {
         inst_x *= bw;
         inst_y *= bh;
@@ -79,16 +87,15 @@ void gerbolyze::Pattern::tile (xform2d &mat, const gerbolyze::RenderSettings &rs
 
     /* Switch to pattern coordinates */
     xform2d local_xf(mat);
-    local_xf.translate(bx, by);
     local_xf.transform(patternTransform);
 
     /* Iterate over all pattern tiles in pattern coordinates */
-    for (double inst_off_x = fmod(inst_x, inst_w) - inst_w;
-            inst_off_x < bw + inst_w;
+    for (double inst_off_x = fmod(inst_x, inst_w) - 2*inst_w;
+            inst_off_x < bw + 2*inst_w;
             inst_off_x += inst_w) {
 
-        for (double inst_off_y = fmod(inst_y, inst_h) - inst_h;
-                inst_off_y < bh + inst_h;
+        for (double inst_off_y = fmod(inst_y, inst_h) - 2*inst_h;
+                inst_off_y < bh + 2*inst_h;
                 inst_off_y += inst_h) {
 
             xform2d elem_xf(local_xf);

svg-flatten/src/vec_core.cpp

@@ -170,8 +170,8 @@ void gerbolyze::VoronoiVectorizer::vectorize_image(xform2d &mat, const pugi::xml
 
     /* Set up target transform using SVG transform and x/y attributes */
     xform2d local_xf(mat);
-    local_xf.transform(xform2d(node.attribute("transform").value()));
     local_xf.translate(x, y);
+    local_xf.transform(xform2d(node.attribute("transform").value()));
 
     double orig_rows = img.rows;
     double orig_cols = img.cols;