[gtk/path-stroke: 360/361] stroke: Add back some debugging

[Matthias Clasen <matthiasc src gnome org>]

commit 068f5005de331895b327de6a1768d9c71a7ab9f7
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Dec 17 23:26:26 2020 -0500

    stroke: Add back some debugging
    
    Draw the on-curve points if STROKE_DEBUG is set.
    This shows how we subdivide curves.

 gsk/gskpathstroke.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
---
diff --git a/gsk/gskpathstroke.c b/gsk/gskpathstroke.c
index d14a18290a..244e040258 100644
--- a/gsk/gskpathstroke.c
+++ b/gsk/gskpathstroke.c
@@ -26,6 +26,8 @@
 #include "gskpathdashprivate.h"
 #include "gskpathopprivate.h"
 
+#define STROKE_DEBUG
+
 #define RAD_TO_DEG(r) ((r)*180.0/M_PI)
 #define DEG_TO_RAD(d) ((d)*M_PI/180.0)
 
@@ -358,6 +360,10 @@ typedef struct
   GskCurve c0; // first segment of the path
   GskCurve l0; // first segment of left contour
   GskCurve r0; // first segment of right contour
+
+#ifdef STROKE_DEBUG
+  GskPathBuilder *debug;
+#endif
 } StrokeData;
 
 static void
@@ -486,6 +492,41 @@ add_segments (StrokeData     *stroke_data,
   stroke_data->l = *l;
 }
 
+#ifdef STROKE_DEBUG
+static void
+add_debug (StrokeData     *stroke_data,
+           const GskCurve *curve)
+{
+  const graphene_point_t *p;
+
+  if (g_getenv ("STROKE_DEBUG"))
+    {
+      switch (curve->op)
+        {
+        case GSK_PATH_LINE:
+        case GSK_PATH_CLOSE:
+          p = curve->line.points;
+          gsk_path_builder_add_circle (stroke_data->debug, &p[0], 3);
+          gsk_path_builder_add_circle (stroke_data->debug, &p[1], 3);
+          break;
+        case GSK_PATH_CURVE:
+          p = curve->curve.points;
+          gsk_path_builder_add_circle (stroke_data->debug, &p[0], 3);
+          gsk_path_builder_add_circle (stroke_data->debug, &p[3], 3);
+          break;
+        case GSK_PATH_CONIC:
+          p = curve->conic.points;
+          gsk_path_builder_add_circle (stroke_data->debug, &p[0], 3);
+          gsk_path_builder_add_circle (stroke_data->debug, &p[3], 3);
+          break;
+        case GSK_PATH_MOVE:
+        default:
+          g_assert_not_reached ();
+        }
+    }
+}
+#endif
+
 /* Add a curve to the in-progress stroke. We look at the angle between
  * the previous curve and this one to determine on which side we need
  * to intersect the curves, and on which to add a join.
@@ -499,6 +540,10 @@ add_curve (StrokeData     *stroke_data,
   gsk_curve_offset (curve, - stroke_data->stroke->line_width / 2, &l);
   gsk_curve_offset (curve, stroke_data->stroke->line_width / 2, &r);
 
+#ifdef STROKE_DEBUG
+  add_debug (stroke_data, curve);
+#endif
+
   if (!stroke_data->has_current_curve)
     {
       stroke_data->c0 = *curve;
@@ -896,6 +941,10 @@ gsk_contour_default_add_stroke (const GskContour *contour,
   stroke_data.builder = builder;
   stroke_data.stroke = stroke;
 
+#ifdef STROKE_DEBUG
+  stroke_data.debug = gsk_path_builder_new ();
+#endif
+
   if (stroke->dash_length <= 0)
     gsk_contour_foreach (contour, GSK_PATH_TOLERANCE_DEFAULT, stroke_op, &stroke_data);
   else
@@ -903,6 +952,12 @@ gsk_contour_default_add_stroke (const GskContour *contour,
 
   if (stroke_data.has_current_point)
     cap_and_connect_contours (&stroke_data);
+
+#ifdef STROKE_DEBUG
+  GskPath *path = gsk_path_builder_free_to_path (stroke_data.debug);
+  gsk_path_builder_add_path (builder, path);
+  gsk_path_unref (path);
+#endif
 }
 
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