OpenVG 1.0 State Tracker

Import of the OpenVG 1.0 state tracker for Gallium.

1 files changed, 1349 insertions, 0 deletions

diff --git a/src/gallium/state_trackers/vega/stroker.c b/src/gallium/state_trackers/vega/stroker.c
new file mode 100644
index 0000000000..1b92d2b5c6
--- /dev/null
+++ b/src/gallium/state_trackers/vega/stroker.c
@@ -0,0 +1,1349 @@
+/**************************************************************************
+ *
+ * Copyright 2009 VMware, Inc.  All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include "stroker.h"
+
+#include "path.h"
+#include "vg_state.h"
+#include "util_array.h"
+#include "arc.h"
+#include "bezier.h"
+#include "matrix.h"
+#include "path_utils.h"
+#include "polygon.h"
+
+#include "math.h"
+
+#ifndef M_2PI
+#define M_2PI 6.28318530717958647692528676655900576
+#endif
+
+#define STROKE_SEGMENTS 0
+#define STROKE_DEBUG 0
+#define DEBUG_EMITS 0
+
+static const VGfloat curve_threshold = 0.25f;
+
+static const VGfloat zero_coords[] = {0.f, 0.f};
+
+enum intersection_type {
+   NoIntersections,
+   BoundedIntersection,
+   UnboundedIntersection,
+};
+
+enum line_join_mode {
+   FlatJoin,
+   SquareJoin,
+   MiterJoin,
+   RoundJoin,
+   RoundCap
+};
+
+struct stroke_iterator {
+   void (*next)(struct stroke_iterator *);
+   VGboolean (*has_next)(struct stroke_iterator *);
+
+   VGPathCommand (*current_command)(struct stroke_iterator *it);
+   void (*current_coords)(struct stroke_iterator *it, VGfloat *coords);
+
+   VGint position;
+   VGint coord_position;
+
+   const VGubyte *cmds;
+   const VGfloat *coords;
+   VGint num_commands;
+   VGint num_coords;
+
+   struct polygon *curve_poly;
+   VGint curve_index;
+};
+
+static VGPathCommand stroke_itr_command(struct stroke_iterator *itr)
+{
+   return itr->current_command(itr);
+}
+
+static void stroke_itr_coords(struct stroke_iterator *itr, VGfloat *coords)
+{
+   itr->current_coords(itr, coords);
+}
+
+static void stroke_fw_itr_coords(struct stroke_iterator *itr, VGfloat *coords)
+{
+   if (itr->position >= itr->num_commands)
+      return;
+   switch (stroke_itr_command(itr)) {
+   case VG_MOVE_TO_ABS:
+      coords[0] = itr->coords[itr->coord_position];
+      coords[1] = itr->coords[itr->coord_position + 1];
+      break;
+   case VG_LINE_TO_ABS:
+      coords[0] = itr->coords[itr->coord_position];
+      coords[1] = itr->coords[itr->coord_position + 1];
+      break;
+   case VG_CUBIC_TO_ABS:
+      coords[0] = itr->coords[itr->coord_position];
+      coords[1] = itr->coords[itr->coord_position + 1];
+      coords[2] = itr->coords[itr->coord_position + 2];
+      coords[3] = itr->coords[itr->coord_position + 3];
+      coords[4] = itr->coords[itr->coord_position + 4];
+      coords[5] = itr->coords[itr->coord_position + 5];
+      break;
+   default:
+      debug_assert(!"invalid command!\n");
+   }
+}
+
+
+static void stroke_bw_itr_coords(struct stroke_iterator *itr, VGfloat *coords)
+{
+   if (itr->position >= itr->num_commands)
+      return;
+   switch (stroke_itr_command(itr)) {
+   case VG_MOVE_TO_ABS:
+      coords[0] = itr->coords[itr->coord_position];
+      coords[1] = itr->coords[itr->coord_position + 1];
+      break;
+   case VG_LINE_TO_ABS:
+      coords[0] = itr->coords[itr->coord_position];
+      coords[1] = itr->coords[itr->coord_position + 1];
+      break;
+   case VG_CUBIC_TO_ABS:
+      coords[0] = itr->coords[itr->coord_position + 4];
+      coords[1] = itr->coords[itr->coord_position + 5];
+      coords[2] = itr->coords[itr->coord_position + 2];
+      coords[3] = itr->coords[itr->coord_position + 3];
+      coords[4] = itr->coords[itr->coord_position + 0];
+      coords[5] = itr->coords[itr->coord_position + 1];
+      break;
+   default:
+      debug_assert(!"invalid command!\n");
+   }
+}
+
+
+static VGPathCommand stroke_fw_current_command(struct stroke_iterator *it)
+{
+   return it->cmds[it->position];
+}
+
+static VGPathCommand stroke_bw_current_command(struct stroke_iterator *it)
+{
+   VGPathCommand prev_cmd;
+   if (it->position == it->num_commands  -1)
+      return VG_MOVE_TO_ABS;
+
+   prev_cmd = it->cmds[it->position + 1];
+   return prev_cmd;
+}
+
+static VGboolean stroke_fw_has_next(struct stroke_iterator *itr)
+{
+   return itr->position < (itr->num_commands - 1);
+}
+
+static VGboolean stroke_bw_has_next(struct stroke_iterator *itr)
+{
+   return itr->position > 0;
+}
+
+static void stroke_fw_next(struct stroke_iterator *itr)
+{
+   VGubyte cmd;
+   debug_assert(stroke_fw_has_next(itr));
+
+   cmd = stroke_itr_command(itr);
+
+   itr->coord_position += num_elements_for_segments(&cmd, 1);
+   ++itr->position;
+}
+
+static void stroke_bw_next(struct stroke_iterator *itr)
+{
+   VGubyte cmd;
+   debug_assert(stroke_bw_has_next(itr));
+
+   --itr->position;
+   cmd = stroke_itr_command(itr);
+
+   itr->coord_position -= num_elements_for_segments(&cmd, 1);
+}
+
+static void stroke_itr_common_init(struct stroke_iterator *itr,
+                                   struct array *cmds,
+                                   struct array *coords)
+{
+   itr->cmds = (VGubyte*)cmds->data;
+   itr->num_commands = cmds->num_elements;
+
+   itr->coords = (VGfloat*)coords->data;
+   itr->num_coords = coords->num_elements;
+}
+
+static void stroke_forward_iterator(struct stroke_iterator *itr,
+                                    struct array *cmds,
+                                    struct array *coords)
+{
+   stroke_itr_common_init(itr, cmds, coords);
+   itr->position = 0;
+   itr->coord_position = 0;
+
+   itr->next = stroke_fw_next;
+   itr->has_next = stroke_fw_has_next;
+   itr->current_command = stroke_fw_current_command;
+   itr->current_coords = stroke_fw_itr_coords;
+}
+
+static void stroke_backward_iterator(struct stroke_iterator *itr,
+                                     struct array *cmds,
+                                     struct array *coords)
+{
+   VGubyte cmd;
+   stroke_itr_common_init(itr, cmds, coords);
+   itr->position = itr->num_commands - 1;
+
+   cmd = stroke_bw_current_command(itr);
+   itr->coord_position = itr->num_coords -
+                         num_elements_for_segments(&cmd, 1);
+
+   itr->next = stroke_bw_next;
+   itr->has_next = stroke_bw_has_next;
+   itr->current_command = stroke_bw_current_command;
+   itr->current_coords = stroke_bw_itr_coords;
+}
+
+
+
+static void stroke_flat_next(struct stroke_iterator *itr)
+{
+   VGubyte cmd;
+
+   if (itr->curve_index >= 0) {
+      ++itr->curve_index;
+      if (itr->curve_index >= polygon_vertex_count(itr->curve_poly)) {
+         itr->curve_index = -1;
+         polygon_destroy(itr->curve_poly);
+         itr->curve_poly = 0;
+      } else
+         return;
+   }
+   debug_assert(stroke_fw_has_next(itr));
+
+   cmd = itr->cmds[itr->position];
+   itr->coord_position += num_elements_for_segments(&cmd, 1);
+   ++itr->position;
+
+   cmd = itr->cmds[itr->position];
+
+   if (cmd == VG_CUBIC_TO_ABS) {
+      struct bezier bezier;
+      VGfloat bez[8];
+
+      bez[0] = itr->coords[itr->coord_position - 2];
+      bez[1] = itr->coords[itr->coord_position - 1];
+      bez[2] = itr->coords[itr->coord_position];
+      bez[3] = itr->coords[itr->coord_position + 1];
+      bez[4] = itr->coords[itr->coord_position + 2];
+      bez[5] = itr->coords[itr->coord_position + 3];
+      bez[6] = itr->coords[itr->coord_position + 4];
+      bez[7] = itr->coords[itr->coord_position + 5];
+
+      bezier_init(&bezier,
+                  bez[0], bez[1],
+                  bez[2], bez[3],
+                  bez[4], bez[5],
+                  bez[6], bez[7]);
+      /* skip the first one, it's the same as the prev point */
+      itr->curve_index = 1;
+      if (itr->curve_poly) {
+         polygon_destroy(itr->curve_poly);
+         itr->curve_poly = 0;
+      }
+      itr->curve_poly = bezier_to_polygon(&bezier);
+   }
+}
+
+static VGboolean stroke_flat_has_next(struct stroke_iterator *itr)
+{
+   return  (itr->curve_index >= 0 &&
+            itr->curve_index < (polygon_vertex_count(itr->curve_poly)-1))
+            || itr->position < (itr->num_commands - 1);
+}
+
+static VGPathCommand stroke_flat_current_command(struct stroke_iterator *it)
+{
+   if (it->cmds[it->position] == VG_CUBIC_TO_ABS) {
+      return VG_LINE_TO_ABS;
+   }
+   return it->cmds[it->position];
+}
+
+static void stroke_flat_itr_coords(struct stroke_iterator *itr, VGfloat *coords)
+{
+   if (itr->curve_index <= -1 && itr->position >= itr->num_commands)
+      return;
+
+   if (itr->curve_index >= 0) {
+      polygon_vertex(itr->curve_poly, itr->curve_index,
+                     coords);
+      return;
+   }
+
+   switch (stroke_itr_command(itr)) {
+   case VG_MOVE_TO_ABS:
+      coords[0] = itr->coords[itr->coord_position];
+      coords[1] = itr->coords[itr->coord_position + 1];
+      break;
+   case VG_LINE_TO_ABS:
+      coords[0] = itr->coords[itr->coord_position];
+      coords[1] = itr->coords[itr->coord_position + 1];
+      break;
+   case VG_CUBIC_TO_ABS:
+   default:
+      debug_assert(!"invalid command!\n");
+   }
+}
+
+static void stroke_flat_iterator(struct stroke_iterator *itr,
+                                 struct array *cmds,
+                                 struct array *coords)
+{
+   stroke_itr_common_init(itr, cmds, coords);
+   itr->position = 0;
+   itr->coord_position = 0;
+
+   itr->next = stroke_flat_next;
+   itr->has_next = stroke_flat_has_next;
+   itr->current_command = stroke_flat_current_command;
+   itr->current_coords = stroke_flat_itr_coords;
+   itr->curve_index = -1;
+   itr->curve_poly = 0;
+}
+
+
+static INLINE VGboolean finite_coords4(const VGfloat *c)
+{
+   return
+      isfinite(c[0]) && isfinite(c[1]) &&
+      isfinite(c[2]) && isfinite(c[3]);
+}
+
+/* from Graphics Gems II */
+#define SAME_SIGNS(a, b) ((a) * (b) >= 0)
+static VGboolean do_lines_intersect(VGfloat x1, VGfloat y1, VGfloat x2, VGfloat y2,
+                                    VGfloat x3, VGfloat y3, VGfloat x4, VGfloat y4)
+{
+   VGfloat a1, a2, b1, b2, c1, c2; /* Coefficients of line eqns */
+   VGfloat r1, r2, r3, r4;         /* 'sign' values */
+
+   a1 = y2 - y1;
+   b1 = x1 - x2;
+   c1 = x2 * y1 - x1 * y2;
+
+   r3 = a1 * x3 + b1 * y3 + c1;
+   r4 = a1 * x4 + b1 * y4 + c1;
+
+   if (r3 != 0 && r4 != 0 && SAME_SIGNS(r3, r4))
+      return VG_FALSE;
+
+   a2 = y4 - y3;
+   b2 = x3 - x4;
+   c2 = x4 * y3 - x3 * y4;
+
+   r1 = a2 * x1 + b2 * y1 + c2;
+   r2 = a2 * x2 + b2 * y2 + c2;
+
+   if (r1 != 0 && r2 != 0 && SAME_SIGNS(r1, r2))
+      return VG_FALSE;
+
+   return VG_TRUE;
+}
+
+static INLINE VGfloat line_dx(const VGfloat *l)
+{
+   return l[2] - l[0];
+}
+
+static INLINE VGfloat line_dy(const VGfloat *l)
+{
+   return l[3] - l[1];
+}
+
+static INLINE VGfloat line_angle(const VGfloat *l)
+{
+   const VGfloat dx = line_dx(l);
+   const VGfloat dy = line_dy(l);
+
+   const VGfloat theta = atan2(-dy, dx) * 360.0 / M_2PI;
+
+   const VGfloat theta_normalized = theta < 0 ? theta + 360 : theta;
+
+   if (floatsEqual(theta_normalized, 360.f))
+      return 0;
+   else
+      return theta_normalized;
+}
+
+static INLINE void line_set_length(VGfloat *l, VGfloat len)
+{
+   VGfloat uv[] = {l[0], l[1], l[2], l[3]};
+   if (null_line(l))
+      return;
+   line_normalize(uv);
+   l[2] = l[0] + line_dx(uv) * len;
+   l[3] = l[1] + line_dy(uv) * len;
+}
+
+static INLINE void line_translate(VGfloat *l, VGfloat x, VGfloat y)
+{
+   l[0] += x;
+   l[1] += y;
+   l[2] += x;
+   l[3] += y;
+}
+
+static INLINE VGfloat line_angle_to(const VGfloat *l1,
+                                    const VGfloat *l2)
+{
+   VGfloat a1, a2, delta, delta_normalized;
+   if (null_line(l1) || null_line(l1))
+      return 0;
+
+   a1 = line_angle(l1);
+   a2 = line_angle(l2);
+
+   delta = a2 - a1;
+   delta_normalized = delta < 0 ? delta + 360 : delta;
+
+   if (floatsEqual(delta, 360.f))
+      return 0;
+   else
+      return delta_normalized;
+}
+
+static INLINE VGfloat line_angles(const VGfloat *l1,
+                                  const VGfloat *l2)
+{
+   VGfloat cos_line, rad = 0;
+
+   if (null_line(l1) || null_line(l2))
+      return 0;
+
+   cos_line = (line_dx(l1)*line_dx(l2) + line_dy(l1)*line_dy(l2)) /
+              (line_lengthv(l1)*line_lengthv(l2));
+   rad = 0;
+
+   if (cos_line >= -1.0 && cos_line <= 1.0)
+      rad = acos(cos_line);
+   return rad * 360 / M_2PI;
+}
+
+
+static INLINE VGfloat adapted_angle_on_x(const VGfloat *line)
+{
+   const VGfloat identity[] = {0, 0, 1, 0};
+   VGfloat angle = line_angles(line, identity);
+   if (line_dy(line) > 0)
+      angle = 360 - angle;
+   return angle;
+}
+
+static enum intersection_type line_intersect(const VGfloat *l1,
+                                             const VGfloat *l2,
+                                             float *intersection_point)
+{
+   VGfloat isect[2];
+   enum intersection_type type;
+   VGboolean dx_zero, ldx_zero;
+
+   if (null_line(l1) || null_line(l2) ||
+       !finite_coords4(l1) || !finite_coords4(l2))
+      return NoIntersections;
+
+   type = do_lines_intersect(l1[0], l1[1], l1[2], l1[3], l2[0], l2[1], l2[2], l2[3])
+          ? BoundedIntersection : UnboundedIntersection;
+
+   dx_zero  = floatsEqual(line_dx(l1) + 1, 1);
+   ldx_zero = floatsEqual(line_dx(l2) + 1, 1);
+
+   /* one of the lines is vertical */
+   if (dx_zero && ldx_zero) {
+      type = NoIntersections;
+   } else if (dx_zero) {
+      VGfloat la = line_dy(l2) / line_dx(l2);
+      isect[0] = l1[0];
+      isect[1] = la * l1[0] + l2[1] - la * l2[0];
+   } else if (ldx_zero) {
+      VGfloat ta = line_dy(l1) / line_dx(l1);
+      isect[0] = l2[0];
+      isect[1] = ta * l2[0] + l1[1] - ta*l1[0];
+   } else {
+      VGfloat x;
+      VGfloat ta = line_dy(l1) / line_dx(l1);
+      VGfloat la = line_dy(l2) / line_dx(l2);
+      if (ta == la)
+         return NoIntersections;
+
+      x = ( - l2[1] + la * l2[0] + l1[1] - ta * l1[0] ) / (la - ta);
+      isect[0] = x;
+      isect[1] = ta*(x - l1[0]) + l1[1];
+   }
+   if (intersection_point) {
+      intersection_point[0] = isect[0];
+      intersection_point[1] = isect[1];
+   }
+   return type;
+}
+
+static INLINE enum line_join_mode stroker_join_mode(struct stroker *s)
+{
+   switch(s->join_style) {
+   case VG_JOIN_MITER:
+      return MiterJoin;
+   case VG_JOIN_ROUND:
+      return RoundJoin;
+   case VG_JOIN_BEVEL:
+      return FlatJoin;
+   default:
+      return FlatJoin;
+   }
+}
+
+static INLINE enum line_join_mode stroker_cap_mode(struct stroker *s)
+{
+   switch(s->cap_style) {
+   case VG_CAP_BUTT:
+      return FlatJoin;
+   case VG_CAP_ROUND:
+      return RoundCap;
+   case VG_CAP_SQUARE:
+      return SquareJoin;
+   default:
+      return FlatJoin;
+   }
+}
+
+void stroker_emit_move_to(struct stroker *stroker, VGfloat x, VGfloat y)
+{
+   VGubyte cmds = VG_MOVE_TO_ABS;
+   VGfloat coords[2] = {x, y};
+#if DEBUG_EMITS
+   debug_printf("emit move %f, %f\n", x, y);
+#endif
+   stroker->back2_x = stroker->back1_x;
+   stroker->back2_y = stroker->back1_y;
+   stroker->back1_x = x;
+   stroker->back1_y = y;
+
+   path_append_data(stroker->path,
+                    1,
+                    &cmds, &coords);
+}
+
+void stroker_emit_line_to(struct stroker *stroker, VGfloat x, VGfloat y)
+{
+   VGubyte cmds = VG_LINE_TO_ABS;
+   VGfloat coords[2] = {x, y};
+#if DEBUG_EMITS
+   debug_printf("emit line %f, %f\n", x, y);
+#endif
+   stroker->back2_x = stroker->back1_x;
+   stroker->back2_y = stroker->back1_y;
+   stroker->back1_x = x;
+   stroker->back1_y = y;
+   path_append_data(stroker->path,
+                    1,
+                    &cmds, &coords);
+}
+
+void stroker_emit_curve_to(struct stroker *stroker, VGfloat px1, VGfloat py1,
+                                  VGfloat px2, VGfloat py2,
+                                  VGfloat x, VGfloat y)
+{
+   VGubyte cmds = VG_CUBIC_TO_ABS;
+   VGfloat coords[6] = {px1, py1, px2, py2, x, y};
+#if DEBUG_EMITS
+   debug_printf("emit curve %f, %f, %f, %f, %f, %f\n", px1, py1,
+                px2, py2, x, y);
+#endif
+
+   if (px2 == x && py2 == y) {
+      if (px1 == x && py1 == y) {
+         stroker->back2_x = stroker->back1_x;
+         stroker->back2_y = stroker->back1_y;
+      } else {
+         stroker->back2_x = px1;
+         stroker->back2_y = py1;
+      }
+   } else {
+      stroker->back2_x = px2;
+      stroker->back2_y = py2;
+   }
+   stroker->back1_x = x;
+   stroker->back1_y = y;
+
+   path_append_data(stroker->path,
+                    1,
+                    &cmds, &coords);
+}
+
+static INLINE void create_round_join(struct stroker *stroker,
+                                     VGfloat x1, VGfloat y1,
+                                     VGfloat x2, VGfloat y2,
+                                     VGfloat width, VGfloat height)
+{
+   struct arc arc;
+   struct matrix matrix;
+
+   matrix_load_identity(&matrix);
+
+   /*stroker_emit_line_to(stroker, nx, ny);*/
+
+   arc_init(&arc, VG_SCCWARC_TO_ABS,
+            x1, y1, x2, y2, width/2, height/2, 0);
+   arc_stroker_emit(&arc, stroker, &matrix);
+}
+
+
+static void create_joins(struct stroker *stroker,
+                         VGfloat focal_x, VGfloat focal_y,
+                         const VGfloat *next_line, enum line_join_mode join)
+{
+#if DEBUG_EMITS
+   debug_printf("create_joins: focal=[%f, %f], next_line=[%f, %f,%f, %f]\n",
+                focal_x, focal_y,
+                next_line[0], next_line[1], next_line[2], next_line[3]);
+#endif
+   /* if we're alredy connected do nothing */
+   if (floatsEqual(stroker->back1_x, next_line[0]) &&
+       floatsEqual(stroker->back1_y, next_line[1]))
+      return;
+
+   if (join == FlatJoin) {
+      stroker_emit_line_to(stroker, next_line[0], next_line[1]);
+   } else {
+      VGfloat prev_line[] = {stroker->back2_x, stroker->back2_y,
+                             stroker->back1_x, stroker->back1_y};
+
+      VGfloat isect[2];
+      enum intersection_type type = line_intersect(prev_line, next_line, isect);
+
+      if (join == SquareJoin) {
+         VGfloat offset = stroker->stroke_width / 2;
+         VGfloat l1[4] = {prev_line[0],
+                          prev_line[1],
+                          prev_line[2],
+                          prev_line[3]};
+         VGfloat l2[4] = {next_line[2],
+                          next_line[3],
+                          next_line[0],
+                          next_line[1]};
+
+         line_translate(l1, line_dx(l1), line_dy(l1));
+         line_set_length(l1, offset);
+
+         line_translate(l2, line_dx(l2), line_dy(l2));
+         line_set_length(l2, offset);
+
+         stroker_emit_line_to(stroker, l1[2], l1[3]);
+         stroker_emit_line_to(stroker, l2[2], l2[3]);
+         stroker_emit_line_to(stroker, l2[0], l2[1]);
+      } else if (join == RoundJoin) {
+         VGfloat offset = stroker->stroke_width / 2;
+         VGfloat short_cut[4] = {prev_line[2], prev_line[3],
+                                 next_line[0], next_line[1]};
+         VGfloat angle = line_angles(prev_line, short_cut);
+
+         if (type == BoundedIntersection ||
+             (angle > 90 && !floatsEqual(angle, 90.f))) {
+            stroker_emit_line_to(stroker, next_line[0], next_line[1]);
+            return;
+         }
+         create_round_join(stroker, prev_line[2], prev_line[3],
+                           next_line[0], next_line[1],
+                           offset * 2, offset * 2);
+
+         stroker_emit_line_to(stroker, next_line[0], next_line[1]);
+      } else if (join == RoundCap) {
+         VGfloat offset = stroker->stroke_width / 2;
+         VGfloat l1[4] = { prev_line[0], prev_line[1],
+                           prev_line[2], prev_line[3] };
+         VGfloat l2[4] = {focal_x, focal_y,
+                          prev_line[2], prev_line[3]};
+
+         line_translate(l1, line_dx(l1), line_dy(l1));
+         line_set_length(l1, KAPPA * offset);
+
+         /* normal between prev_line and focal */
+         line_translate(l2, -line_dy(l2), line_dx(l2));
+         line_set_length(l2, KAPPA * offset);
+
+         stroker_emit_curve_to(stroker, l1[2], l1[3],
+                               l2[2], l2[3],
+                               l2[0], l2[1]);
+
+         l2[0] = l2[0];
+         l2[1] = l2[1];
+         l2[2] = l2[0] - line_dx(l2);
+         l2[3] = l2[1] - line_dy(l2);
+
+         line_translate(l1, next_line[0] - l1[0], next_line[1] - l1[1]);
+
+         stroker_emit_curve_to(stroker,
+                               l2[2], l2[3],
+                               l1[2], l1[3],
+                               l1[0], l1[1]);
+      } else if (join == MiterJoin) {
+         VGfloat miter_line[4] = {stroker->back1_x, stroker->back1_y,
+                                  isect[0], isect[1]};
+         VGfloat sl = (stroker->stroke_width * stroker->miter_limit);
+         VGfloat inside_line[4] = {prev_line[2], prev_line[3],
+                                   next_line[0], next_line[1]};
+         VGfloat angle = line_angle_to(inside_line, prev_line);
+
+         if (type == BoundedIntersection ||
+             (angle > 90 && !floatsEqual(angle, 90.f))) {
+            /*
+            debug_printf("f = %f, nl = %f, pl = %f, is = %f\n",
+                         focal_x, next_line[0],
+                         prev_line[2], isect[0]);*/
+            stroker_emit_line_to(stroker, next_line[0], next_line[1]);
+            return;
+         }
+
+         if (type == NoIntersections || line_lengthv(miter_line) > sl) {
+            stroker_emit_line_to(stroker, next_line[0], next_line[1]);
+         } else {
+            stroker_emit_line_to(stroker, isect[0], isect[1]);
+            stroker_emit_line_to(stroker, next_line[0], next_line[1]);
+         }
+      } else {
+         debug_assert(!"create_joins bad join style");
+      }
+   }
+}
+
+static void stroker_add_segment(struct stroker *stroker,
+                                VGPathCommand cmd,
+                                const VGfloat *coords,
+                                VGint num_coords)
+{
+   /* skip duplicated points */
+   if (stroker->segments->num_elements &&
+       stroker->last_cmd == cmd) {
+      VGfloat *data = stroker->control_points->data;
+      data += stroker->control_points->num_elements;
+      data -= num_coords;
+      switch (cmd) {
+      case VG_MOVE_TO_ABS:
+         if (floatsEqual(coords[0], data[0]) &&
+             floatsEqual(coords[1], data[1]))
+            return;
+         break;
+      case VG_LINE_TO_ABS:
+         if (floatsEqual(coords[0], data[0]) &&
+             floatsEqual(coords[1], data[1]))
+            return;
+         break;
+      case VG_CUBIC_TO_ABS:
+         if (floatsEqual(coords[0], data[0]) &&
+             floatsEqual(coords[1], data[1]) &&
+             floatsEqual(coords[2], data[2]) &&
+             floatsEqual(coords[3], data[3]) &&
+             floatsEqual(coords[4], data[4]) &&
+             floatsEqual(coords[5], data[5]))
+            return;
+         break;
+      default:
+         debug_assert(!"Invalid stroke segment");
+      }
+   } else if (stroker->last_cmd == VG_CUBIC_TO_ABS &&
+              cmd == VG_LINE_TO_ABS) {
+      VGfloat *data = stroker->control_points->data;
+      data += stroker->control_points->num_elements;
+      data -= 2;
+      if (floatsEqual(coords[0], data[0]) &&
+          floatsEqual(coords[1], data[1]))
+         return;
+   }
+   stroker->last_cmd = cmd;
+   array_append_data(stroker->segments, &cmd, 1);
+   array_append_data(stroker->control_points, coords, num_coords);
+}
+
+void stroker_move_to(struct stroker *stroker, VGfloat x, VGfloat y)
+{
+   VGfloat coords[2] = {x, y};
+#if STROKE_SEGMENTS
+   debug_printf("stroker_move_to(%f, %f)\n", x, y);
+#endif
+
+   if (stroker->segments->num_elements > 0)
+      stroker->process_subpath(stroker);
+
+   array_reset(stroker->segments);
+   array_reset(stroker->control_points);
+
+   stroker_add_segment(stroker, VG_MOVE_TO_ABS, coords, 2);
+}
+
+void stroker_line_to(struct stroker *stroker, VGfloat x, VGfloat y)
+{
+   VGfloat coords[] = {x, y};
+
+#if STROKE_SEGMENTS
+   debug_printf("stroker_line_to(%f, %f)\n", x, y);
+#endif
+   if (!stroker->segments->num_elements)
+      stroker_add_segment(stroker, VG_MOVE_TO_ABS, zero_coords, 2);
+
+   stroker_add_segment(stroker, VG_LINE_TO_ABS, coords, 2);
+}
+
+void stroker_curve_to(struct stroker *stroker, VGfloat px1, VGfloat py1,
+                      VGfloat px2, VGfloat py2,
+                      VGfloat x, VGfloat y)
+{
+   VGfloat coords[] = {px1, py1,
+                       px2, py2,
+                       x, y};
+#if STROKE_SEGMENTS
+   debug_printf("stroker_curve_to(%f, %f, %f, %f, %f, %f)\n",
+                px1, py1, px2, py2, x, y);
+#endif
+   if (!stroker->segments->num_elements)
+      stroker_add_segment(stroker, VG_MOVE_TO_ABS, zero_coords, 2);
+
+   stroker_add_segment(stroker, VG_CUBIC_TO_ABS, coords, 6);
+}
+
+static INLINE VGboolean is_segment_null(VGPathCommand cmd,
+                                        VGfloat *coords,
+                                        VGfloat *res)
+{
+   switch(cmd) {
+   case VG_MOVE_TO_ABS:
+   case VG_LINE_TO_ABS:
+      return floatsEqual(coords[0], res[0]) &&
+         floatsEqual(coords[1], res[1]);
+      break;
+   case VG_CUBIC_TO_ABS:
+      return floatsEqual(coords[0], res[0]) &&
+         floatsEqual(coords[1], res[1]) &&
+         floatsEqual(coords[2], res[0]) &&
+         floatsEqual(coords[3], res[1]) &&
+         floatsEqual(coords[4], res[0]) &&
+         floatsEqual(coords[5], res[1]);
+      break;
+   default:
+      assert(0);
+   }
+   return VG_FALSE;
+}
+
+static VGboolean vg_stroke_outline(struct stroke_iterator *it,
+                                struct stroker *stroker,
+                                VGboolean cap_first,
+                                VGfloat *start_tangent)
+{
+   const int MAX_OFFSET = 16;
+   struct bezier offset_curves[MAX_OFFSET];
+   VGPathCommand first_element;
+   VGfloat start[2], prev[2];
+   VGboolean first = VG_TRUE;
+   VGfloat offset;
+
+   first_element = stroke_itr_command(it);
+   if (first_element != VG_MOVE_TO_ABS) {
+      stroker_emit_move_to(stroker, 0.f, 0.f);
+      prev[0] = 0.f;
+      prev[1] = 0.f;
+   }
+   stroke_itr_coords(it, start);
+#if STROKE_DEBUG
+   debug_printf(" -> (side) [%.2f, %.2f]\n",
+                start[0],
+                start[1]);
+#endif
+
+   prev[0] = start[0];
+   prev[1] = start[1];
+
+   offset = stroker->stroke_width / 2;
+
+   if (!it->has_next(it)) {
+      /* single point */
+
+      return VG_TRUE;
+   }
+
+   while (it->has_next(it)) {
+      VGPathCommand cmd;
+      VGfloat coords[8];
+
+      it->next(it);
+      cmd = stroke_itr_command(it);
+      stroke_itr_coords(it, coords);
+
+      if (cmd == VG_LINE_TO_ABS) {
+         VGfloat line[4] = {prev[0], prev[1], coords[0], coords[1]};
+         VGfloat normal[4];
+         line_normal(line, normal);
+
+#if STROKE_DEBUG
+         debug_printf("\n ---> (side) lineto [%.2f, %.2f]\n", coords[0], coords[1]);
+#endif
+         line_set_length(normal, offset);
+         line_translate(line, line_dx(normal), line_dy(normal));
+
+         /* if we are starting a new subpath, move to correct starting point */
+         if (first) {
+            if (cap_first)
+               create_joins(stroker, prev[0], prev[1], line,
+                            stroker_cap_mode(stroker));
+            else
+               stroker_emit_move_to(stroker, line[0], line[1]);
+            memcpy(start_tangent, line,
+                   sizeof(VGfloat) * 4);
+            first = VG_FALSE;
+         } else {
+            create_joins(stroker, prev[0], prev[1], line,
+                         stroker_join_mode(stroker));
+         }
+
+         /* add the stroke for this line */
+         stroker_emit_line_to(stroker, line[2], line[3]);
+         prev[0] = coords[0];
+         prev[1] = coords[1];
+      } else if (cmd == VG_CUBIC_TO_ABS) {
+#if STROKE_DEBUG
+         debug_printf("\n ---> (side) cubicTo [%.2f, %.2f]\n",
+                coords[4],
+                coords[5]);
+#endif
+         struct bezier bezier;
+         int count;
+
+         bezier_init(&bezier,
+                     prev[0], prev[1], coords[0], coords[1],
+                     coords[2], coords[3], coords[4], coords[5]);
+
+         count = bezier_translate_by_normal(&bezier,
+                                            offset_curves,
+                                            MAX_OFFSET,
+                                            offset,
+                                            curve_threshold);
+
+         if (count) {
+            /* if we are starting a new subpath, move to correct starting point */
+            VGfloat tangent[4];
+            VGint i;
+
+            bezier_start_tangent(&bezier, tangent);
+            line_translate(tangent,
+                           offset_curves[0].x1 - bezier.x1,
+                           offset_curves[0].y1 - bezier.y1);
+            if (first) {
+               VGfloat pt[2] = {offset_curves[0].x1,
+                                offset_curves[0].y1};
+
+               if (cap_first) {
+                  create_joins(stroker, prev[0], prev[1], tangent,
+                               stroker_cap_mode(stroker));
+               } else {
+                  stroker_emit_move_to(stroker, pt[0], pt[1]);
+               }
+               start_tangent[0] = tangent[0];
+               start_tangent[1] = tangent[1];
+               start_tangent[2] = tangent[2];
+               start_tangent[3] = tangent[3];
+               first = VG_FALSE;
+            } else {
+               create_joins(stroker, prev[0], prev[1], tangent,
+                            stroker_join_mode(stroker));
+            }
+
+            /* add these beziers */
+            for (i = 0; i < count; ++i) {
+               struct bezier *bez = &offset_curves[i];
+               stroker_emit_curve_to(stroker,
+                                     bez->x2, bez->y2,
+                                     bez->x3, bez->y3,
+                                     bez->x4, bez->y4);
+            }
+         }
+
+         prev[0] = coords[4];
+         prev[1] = coords[5];
+      }
+   }
+
+   if (floatsEqual(start[0], prev[0]) &&
+       floatsEqual(start[1], prev[1])) {
+      /* closed subpath, join first and last point */
+#if STROKE_DEBUG
+      debug_printf("\n stroker: closed subpath\n");
+#endif
+      create_joins(stroker, prev[0], prev[1], start_tangent,
+                   stroker_join_mode(stroker));
+      return VG_TRUE;
+   } else {
+#if STROKE_DEBUG
+      debug_printf("\n stroker: open subpath\n");
+#endif
+      return VG_FALSE;
+   }
+}
+
+static void stroker_process_subpath(struct stroker *stroker)
+{
+   VGboolean fwclosed, bwclosed;
+   VGfloat fw_start_tangent[4], bw_start_tangent[4];
+   struct stroke_iterator fwit;
+   struct stroke_iterator bwit;
+   debug_assert(stroker->segments->num_elements > 0);
+
+   memset(fw_start_tangent, 0,
+          sizeof(VGfloat)*4);
+   memset(bw_start_tangent, 0,
+          sizeof(VGfloat)*4);
+
+   stroke_forward_iterator(&fwit, stroker->segments,
+                           stroker->control_points);
+   stroke_backward_iterator(&bwit, stroker->segments,
+                            stroker->control_points);
+
+   debug_assert(fwit.cmds[0] == VG_MOVE_TO_ABS);
+
+   fwclosed = vg_stroke_outline(&fwit, stroker, VG_FALSE, fw_start_tangent);
+   bwclosed = vg_stroke_outline(&bwit, stroker, !fwclosed, bw_start_tangent);
+
+   if (!bwclosed)
+      create_joins(stroker,
+                   fwit.coords[0], fwit.coords[1], fw_start_tangent,
+                   stroker_cap_mode(stroker));
+   else {
+      /* hack to handle the requirement of the VG spec that says that strokes
+       * of len==0 that have butt cap or round cap still need
+       * to be rendered. (8.7.4 Stroke Generation) */
+      if (stroker->segments->num_elements <= 3) {
+         VGPathCommand cmd;
+         VGfloat data[8], coords[8];
+         struct stroke_iterator *it = &fwit;
+
+         stroke_forward_iterator(it, stroker->segments,
+                                 stroker->control_points);
+         cmd = stroke_itr_command(it);
+         stroke_itr_coords(it, coords);
+         if (cmd != VG_MOVE_TO_ABS) {
+            memset(data, 0, sizeof(VGfloat) * 8);
+            if (!is_segment_null(cmd, coords, data))
+               return;
+         } else {
+            data[0] = coords[0];
+            data[1] = coords[1];
+         }
+         while (it->has_next(it)) {
+            it->next(it);
+            cmd = stroke_itr_command(it);
+            stroke_itr_coords(it, coords);
+            if (!is_segment_null(cmd, coords, data))
+               return;
+         }
+         /* generate the square/round cap */
+         if (stroker->cap_style == VG_CAP_SQUARE) {
+            VGfloat offset = stroker->stroke_width / 2;
+            stroker_emit_move_to(stroker, data[0] - offset,
+                                 data[1] - offset);
+            stroker_emit_line_to(stroker, data[0] + offset,
+                                 data[1] - offset);
+            stroker_emit_line_to(stroker, data[0] + offset,
+                                 data[1] + offset);
+            stroker_emit_line_to(stroker, data[0] - offset,
+                                 data[1] + offset);
+            stroker_emit_line_to(stroker, data[0] - offset,
+                                 data[1] - offset);
+         } else if (stroker->cap_style == VG_CAP_ROUND) {
+            VGfloat offset = stroker->stroke_width / 2;
+            VGfloat cx = data[0], cy = data[1];
+            { /*circle */
+               struct arc arc;
+               struct matrix matrix;
+               matrix_load_identity(&matrix);
+
+               stroker_emit_move_to(stroker, cx + offset, cy);
+               arc_init(&arc, VG_SCCWARC_TO_ABS,
+                        cx + offset, cy,
+                        cx - offset, cy,
+                        offset, offset, 0);
+               arc_stroker_emit(&arc, stroker, &matrix);
+               arc_init(&arc, VG_SCCWARC_TO_ABS,
+                         cx - offset, cy,
+                         cx + offset, cy,
+                         offset, offset, 0);
+               arc_stroker_emit(&arc, stroker, &matrix);
+            }
+         }
+      }
+   }
+}
+
+static INLINE VGfloat dash_pattern(struct dash_stroker *stroker,
+                                   VGint idx)
+{
+   if (stroker->dash_pattern[idx] < 0)
+      return 0.f;
+   return stroker->dash_pattern[idx];
+}
+
+static void dash_stroker_process_subpath(struct stroker *str)
+{
+   struct dash_stroker *stroker = (struct dash_stroker *)str;
+   VGfloat sum_length = 0;
+   VGint i;
+   VGint idash = 0;
+   VGfloat pos = 0;
+   VGfloat elen = 0;
+   VGfloat doffset = stroker->dash_phase;
+   VGfloat estart = 0;
+   VGfloat estop = 0;
+   VGfloat cline[4];
+   struct stroke_iterator it;
+   VGfloat prev[2];
+   VGfloat move_to_pos[2];
+   VGfloat line_to_pos[2];
+
+   VGboolean has_move_to = VG_FALSE;
+
+   stroke_flat_iterator(&it, stroker->base.segments,
+                        stroker->base.control_points);
+
+   stroke_itr_coords(&it, prev);
+   move_to_pos[0] = prev[0];
+   move_to_pos[1] = prev[1];
+
+   debug_assert(stroker->dash_pattern_num > 0);
+
+   for (i = 0; i < stroker->dash_pattern_num; ++i) {
+      sum_length += dash_pattern(stroker, i);
+   }
+
+   if (floatIsZero(sum_length)) {
+      return;
+   }
+
+   doffset -= floorf(doffset / sum_length) * sum_length;
+
+   while (!floatIsZero(doffset) && doffset >= dash_pattern(stroker, idash)) {
+      doffset -= dash_pattern(stroker, idash);
+      idash = (idash + 1) % stroker->dash_pattern_num;
+   }
+
+   while (it.has_next(&it)) {
+      VGPathCommand cmd;
+      VGfloat coords[8];
+      VGboolean done;
+
+      it.next(&it);
+      cmd = stroke_itr_command(&it);
+      stroke_itr_coords(&it, coords);
+
+      debug_assert(cmd == VG_LINE_TO_ABS);
+      cline[0] = prev[0];
+      cline[1] = prev[1];
+      cline[2] = coords[0];
+      cline[3] = coords[1];
+
+      elen = line_lengthv(cline);
+
+      estop = estart + elen;
+
+      done = pos >= estop;
+      while (!done) {
+         VGfloat p2[2];
+
+         VGint idash_incr = 0;
+         VGboolean has_offset = doffset > 0;
+         VGfloat dpos = pos + dash_pattern(stroker, idash) - doffset - estart;
+
+         debug_assert(dpos >= 0);
+
+         if (dpos > elen) { /* dash extends this line */
+            doffset = dash_pattern(stroker, idash) - (dpos - elen);
+            pos = estop;
+            done = VG_TRUE;
+            p2[0] = cline[2];
+            p2[1] = cline[3];
+         } else { /* Dash is on this line */
+            line_point_at(cline, dpos/elen, p2);
+            pos = dpos + estart;
+            done = pos >= estop;
+            idash_incr = 1;
+            doffset = 0;
+         }
+
+         if (idash % 2 == 0) {
+            line_to_pos[0] = p2[0];
+            line_to_pos[1] = p2[1];
+
+            if (!has_offset || !has_move_to) {
+               stroker_move_to(&stroker->stroker, move_to_pos[0], move_to_pos[1]);
+               has_move_to = VG_TRUE;
+            }
+            stroker_line_to(&stroker->stroker, line_to_pos[0], line_to_pos[1]);
+         } else {
+            move_to_pos[0] = p2[0];
+            move_to_pos[1] = p2[1];
+         }
+
+         idash = (idash + idash_incr) % stroker->dash_pattern_num;
+      }
+
+      estart = estop;
+      prev[0] = coords[0];
+      prev[1] = coords[1];
+   }
+
+   if (it.curve_poly) {
+      polygon_destroy(it.curve_poly);
+      it.curve_poly = 0;
+   }
+
+   stroker->base.path = stroker->stroker.path;
+}
+
+static void default_begin(struct stroker *stroker)
+{
+   array_reset(stroker->segments);
+   array_reset(stroker->control_points);
+}
+
+static void default_end(struct stroker *stroker)
+{
+   if (stroker->segments->num_elements > 0)
+      stroker->process_subpath(stroker);
+}
+
+
+static void dash_stroker_begin(struct stroker *stroker)
+{
+   struct dash_stroker *dasher =
+      (struct dash_stroker *)stroker;
+
+   default_begin(&dasher->stroker);
+   default_begin(stroker);
+}
+
+static void dash_stroker_end(struct stroker *stroker)
+{
+   struct dash_stroker *dasher =
+      (struct dash_stroker *)stroker;
+
+   default_end(stroker);
+   default_end(&dasher->stroker);
+}
+
+void stroker_init(struct stroker *stroker,
+                  struct vg_state *state)
+{
+   stroker->stroke_width = state->stroke.line_width.f;
+   stroker->miter_limit = state->stroke.miter_limit.f;
+   stroker->cap_style = state->stroke.cap_style;
+   stroker->join_style = state->stroke.join_style;
+
+   stroker->begin = default_begin;
+   stroker->process_subpath = stroker_process_subpath;
+   stroker->end = default_end;
+
+   stroker->segments = array_create(sizeof(VGubyte));
+   stroker->control_points = array_create(sizeof(VGfloat));
+
+   stroker->back1_x = 0;
+   stroker->back1_y = 0;
+   stroker->back2_x = 0;
+   stroker->back2_y = 0;
+
+   stroker->path = path_create(VG_PATH_DATATYPE_F, 1.0f, 0.0f,
+                               0, 0, VG_PATH_CAPABILITY_ALL);
+
+   stroker->last_cmd = VG_CLOSE_PATH;
+}
+
+void dash_stroker_init(struct stroker *str,
+                       struct vg_state *state)
+{
+   struct dash_stroker *stroker = (struct dash_stroker *)str;
+   int i;
+
+   stroker_init(str, state);
+   stroker_init(&stroker->stroker, state);
+
+   {
+      int real_num = state->stroke.dash_pattern_num;
+      if (real_num % 2)/* if odd, ignore the last one */
+         --real_num;
+      for (i = 0; i < real_num; ++i)
+         stroker->dash_pattern[i] = state->stroke.dash_pattern[i].f;
+      stroker->dash_pattern_num = real_num;
+   }
+
+   stroker->dash_phase = state->stroke.dash_phase.f;
+   stroker->dash_phase_reset = state->stroke.dash_phase_reset;
+
+   stroker->base.begin = dash_stroker_begin;
+   stroker->base.process_subpath = dash_stroker_process_subpath;
+   stroker->base.end = dash_stroker_end;
+   path_destroy(stroker->base.path);
+   stroker->base.path = NULL;
+}
+
+void stroker_begin(struct stroker *stroker)
+{
+   stroker->begin(stroker);
+}
+
+void stroker_end(struct stroker *stroker)
+{
+   stroker->end(stroker);
+}
+
+void stroker_cleanup(struct stroker *stroker)
+{
+   array_destroy(stroker->segments);
+   array_destroy(stroker->control_points);
+}
+
+void dash_stroker_cleanup(struct dash_stroker *stroker)
+{
+   /* if stroker->base.path is null means we never
+    * processed a valid path so delete the temp one
+    * we already created */
+   if (!stroker->base.path)
+      path_destroy(stroker->stroker.path);
+   stroker_cleanup(&stroker->stroker);
+   stroker_cleanup((struct stroker*)stroker);
+}