initial commit, 4.5 stable

thirdparty/harfbuzz/src/hb-paint-bounded.hh

@@ -0,0 +1,117 @@
+/*
+ * Copyright © 2022 Behdad Esfahbod
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+
+#ifndef HB_PAINT_BOUNDED_HH
+#define HB_PAINT_BOUNDED_HH
+
+#include "hb.hh"
+#include "hb-paint.h"
+
+#include "hb-geometry.hh"
+
+
+typedef struct  hb_paint_bounded_context_t hb_paint_bounded_context_t;
+
+struct hb_paint_bounded_context_t
+{
+  void clear ()
+  {
+    clips = 0;
+    bounded = true;
+    groups.clear ();
+  }
+
+  hb_paint_bounded_context_t ()
+  {
+    clear ();
+  }
+
+  bool is_bounded ()
+  {
+    return bounded;
+  }
+
+  void push_clip ()
+  {
+    clips++;
+  }
+
+  void pop_clip ()
+  {
+    if (clips == 0) return;
+    clips--;
+  }
+
+  void push_group ()
+  {
+    groups.push (bounded);
+    bounded = true;
+  }
+
+  void pop_group (hb_paint_composite_mode_t mode)
+  {
+    const bool src_bounded = bounded;
+    bounded = groups.pop ();
+    bool &backdrop_bounded = bounded;
+
+    // https://learn.microsoft.com/en-us/typography/opentype/spec/colr#format-32-paintcomposite
+    switch ((int) mode)
+    {
+      case HB_PAINT_COMPOSITE_MODE_CLEAR:
+	backdrop_bounded = true;
+	break;
+      case HB_PAINT_COMPOSITE_MODE_SRC:
+      case HB_PAINT_COMPOSITE_MODE_SRC_OUT:
+	backdrop_bounded = src_bounded;
+	break;
+      case HB_PAINT_COMPOSITE_MODE_DEST:
+      case HB_PAINT_COMPOSITE_MODE_DEST_OUT:
+	break;
+      case HB_PAINT_COMPOSITE_MODE_SRC_IN:
+      case HB_PAINT_COMPOSITE_MODE_DEST_IN:
+	backdrop_bounded = backdrop_bounded && src_bounded;
+	break;
+      default:
+	backdrop_bounded = backdrop_bounded || src_bounded;
+	break;
+     }
+  }
+
+  void paint ()
+  {
+    if (!clips)
+      bounded = false;
+  }
+
+  protected:
+  bool bounded; // true if current drawing bounded
+  unsigned clips; // number of active clips
+  hb_vector_t<bool> groups; // true if group bounded
+};
+
+HB_INTERNAL hb_paint_funcs_t *
+hb_paint_bounded_get_funcs ();
+
+
+#endif /* HB_PAINT_BOUNDED_HH */