Use the polygon method to repalce the trace code

Trace code was used by brush, eraser and rainbow tools.
Was replaced in the brush and eraser tools, due to artifacts
when the alpha is not 1.0
The rainbow tools continue using the old code (renamed to _old_trace)

Signed-off-by: Gonzalo Odiard <gonzalo@laptop.org>

1 files changed, 68 insertions, 8 deletions

diff --git a/Desenho.py b/Desenho.py
index fb451a4..f575b83 100644
--- a/Desenho.py
+++ b/Desenho.py
@@ -131,7 +131,6 @@ class Desenho:
             @param  shape -- string (default 'circle')
 
         """
-        widget.drawing_ctx.set_source_rgba(1.0, 1.0, 1.0, 1.0)
         self._trace(widget, coords, last)
 
     def brush(self, widget, coords, last):
@@ -145,7 +144,6 @@ class Desenho:
             @param  shape -- string (default 'circle')
 
         """
-        widget.drawing_ctx.set_source_rgba(*widget.tool['cairo_stroke_color'])
         self._trace(widget, coords, last)
 
     def stamp(self, widget, coords, last, stamp_size=20):
@@ -196,9 +194,12 @@ class Desenho:
 
         widget.drawing_ctx.set_source_rgba(_color.red, _color.green,
                 _color.blue, 0.3)
-        self._trace(widget, coords, last)
+        self._old_trace(widget, coords, last)
 
-    def _trace(self, widget, coords, last):
+    def _old_trace(self, widget, coords, last):
+        """
+        _old_trace is used only by rainbow
+        """
         widget.desenha = False
         size = widget.tool['line size']
         shape = widget.tool['line shape']
@@ -252,6 +253,53 @@ class Desenho:
         else:
             widget.queue_draw()
 
+    def finish_trace(self, widget):
+        widget.desenha = False
+        shape = widget.tool['line shape']
+        rounded = (shape == 'circle')
+        self._draw_polygon(widget, False, False, self.points, False, rounded)
+        if not rounded and len(self.points) == 1:
+            # draw a square if the mouse was not moved
+            size = widget.tool['line size']
+            coords = self.points[0]
+            widget.drawing_ctx.save()
+            if widget.tool['name'] == 'eraser':
+                color = (1.0, 1.0, 1.0, 1.0)
+            else:
+                color = widget.tool['cairo_stroke_color']
+            widget.drawing_ctx.set_source_rgba(*color)
+            widget.drawing_ctx.move_to(coords[0] - size / 2,
+                    coords[1] - size / 2)
+            widget.drawing_ctx.rectangle(coords[0] - size / 2,
+                    coords[1] - size / 2, size, size)
+            widget.drawing_ctx.fill()
+            widget.drawing_ctx.restore()
+
+        self.points = []
+
+    def _trace(self, widget, coords, last):
+        widget.desenha = True
+        size = widget.tool['line size']
+        shape = widget.tool['line shape']
+
+        rounded = (shape == 'circle')
+
+        self.points.append((coords[0], coords[1]))
+        if last:
+            self._draw_polygon(widget, True, False, self.points, False,
+                    rounded)
+
+        if last:
+            x = min(coords[0], last[0])
+            width = max(coords[0], last[0]) - x
+            y = min(coords[1], last[1])
+            height = max(coords[1], last[1]) - y
+            # We add size to avoid drawing dotted lines
+            widget.queue_draw_area(x - size, y - size,
+                width + size * 2, height + size * 2)
+        else:
+            widget.queue_draw()
+
     def square(self, widget, event, coords, temp, fill):
         """Draw a square.
 
@@ -273,10 +321,12 @@ class Desenho:
             ctx.set_source_rgba(*widget.tool['cairo_fill_color'])
             ctx.fill_preserve()
         ctx.set_source_rgba(*widget.tool['cairo_stroke_color'])
+        ctx.set_line_width(widget.tool['line size'])
         ctx.stroke()
         widget.queue_draw_area(x, y, dx, dy)
 
-    def _draw_polygon(self, widget, temp, fill, points, closed=True):
+    def _draw_polygon(self, widget, temp, fill, points, closed=True,
+            rounded=False):
         if not points:
             return
         if temp == True:
@@ -291,12 +341,22 @@ class Desenho:
             ctx.line_to(*point)
         if closed:
             ctx.close_path()
-        ctx.set_line_join(cairo.LINE_JOIN_MITER)
-        ctx.set_line_width(widget.tool['line size'])
+        if rounded:
+            ctx.set_line_cap(cairo.LINE_CAP_ROUND)
+            ctx.set_line_join(cairo.LINE_JOIN_ROUND)
+        else:
+            ctx.set_line_cap(cairo.LINE_CAP_SQUARE)
+            ctx.set_line_join(cairo.LINE_JOIN_MITER)
         if fill:
             ctx.set_source_rgba(*widget.tool['cairo_fill_color'])
+            ctx.set_line_width(0)
             ctx.fill_preserve()
-        ctx.set_source_rgba(*widget.tool['cairo_stroke_color'])
+
+        if widget.tool['name'] == 'eraser':
+            ctx.set_source_rgba(1.0, 1.0, 1.0, 1.0)
+        else:
+            ctx.set_source_rgba(*widget.tool['cairo_stroke_color'])
+        ctx.set_line_width(widget.tool['line size'])
         ctx.stroke()
         ctx.restore()
         widget.queue_draw()