common bezier: code refactoring.

Organize bezier functions for internal share.

this bezier can be used in svg loader.

Change-Id: I78acd3273c0528688ca46ff7c29d78607bd729bd

src/lib/meson.build

@@ -4,12 +4,14 @@ subdir('gl_engine')
 source_file = [
    'tvgCanvasImpl.h',
    'tvgCommon.h',
+   'tvgBezier.h',
    'tvgLoader.h',
    'tvgLoaderMgr.h',
    'tvgRender.h',
    'tvgSceneImpl.h',
    'tvgShapePath.h',
    'tvgShapeImpl.h',
+   'tvgBezier.cpp',
    'tvgCanvas.cpp',
    'tvgFill.cpp',
    'tvgGlCanvas.cpp',

src/lib/sw_engine/tvgSwShape.cpp

@@ -30,15 +30,6 @@ struct Line
 };
 
 
-struct Bezier
-{
-    Point start;
-    Point ctrl1;
-    Point ctrl2;
-    Point end;
-};
-
-
 static float _lineLength(const Point& pt1, const Point& pt2)
 {
     /* approximate sqrt(x*x + y*y) using alpha max plus beta min algorithm.
@@ -64,102 +55,6 @@ static void _lineSplitAt(const Line& cur, float at, Line& left, Line& right)
 }
 
 
-static void _bezSplit(const Bezier&cur, Bezier& left, Bezier& right)
-{
-    auto c = (cur.ctrl1.x + cur.ctrl2.x) * 0.5f;
-    left.ctrl1.x = (cur.start.x + cur.ctrl1.x) * 0.5f;
-    right.ctrl2.x = (cur.ctrl2.x + cur.end.x) * 0.5f;
-    left.start.x = cur.start.x;
-    right.end.x = cur.end.x;
-    left.ctrl2.x = (left.ctrl1.x + c) * 0.5f;
-    right.ctrl1.x = (right.ctrl2.x + c) * 0.5f;
-    left.end.x = right.start.x = (left.ctrl2.x + right.ctrl1.x) * 0.5f;
-
-    c = (cur.ctrl1.y + cur.ctrl2.y) * 0.5f;
-    left.ctrl1.y = (cur.start.y + cur.ctrl1.y) * 0.5f;
-    right.ctrl2.y = (cur.ctrl2.y + cur.end.y) * 0.5f;
-    left.start.y = cur.start.y;
-    right.end.y = cur.end.y;
-    left.ctrl2.y = (left.ctrl1.y + c) * 0.5f;
-    right.ctrl1.y = (right.ctrl2.y + c) * 0.5f;
-    left.end.y = right.start.y = (left.ctrl2.y + right.ctrl1.y) * 0.5f;
-}
-
-
-static float _bezLength(const Bezier& cur)
-{
-    Bezier left, right;
-    auto len = _lineLength(cur.start, cur.ctrl1) + _lineLength(cur.ctrl1, cur.ctrl2) + _lineLength(cur.ctrl2, cur.end);
-    auto chord = _lineLength(cur.start, cur.end);
-
-    if (fabs(len - chord) > FLT_EPSILON) {
-        _bezSplit(cur, left, right);
-        return _bezLength(left) + _bezLength(right);
-    }
-    return len;
-}
-
-
-static void _bezSplitLeft(Bezier& cur, float at, Bezier& left)
-{
-    left.start = cur.start;
-
-    left.ctrl1.x = cur.start.x + at * (cur.ctrl1.x - cur.start.x);
-    left.ctrl1.y = cur.start.y + at * (cur.ctrl1.y - cur.start.y);
-
-    left.ctrl2.x = cur.ctrl1.x + at * (cur.ctrl2.x - cur.ctrl1.x); // temporary holding spot
-    left.ctrl2.y = cur.ctrl1.y + at * (cur.ctrl2.y - cur.ctrl1.y); // temporary holding spot
-
-    cur.ctrl2.x = cur.ctrl2.x + at * (cur.end.x - cur.ctrl2.x);
-    cur.ctrl2.y = cur.ctrl2.y + at * (cur.end.y - cur.ctrl2.y);
-
-    cur.ctrl1.x = left.ctrl2.x + at * (cur.ctrl2.x - left.ctrl2.x);
-    cur.ctrl1.y = left.ctrl2.y + at * (cur.ctrl2.y - left.ctrl2.y);
-
-    left.ctrl2.x = left.ctrl1.x + at * (left.ctrl2.x - left.ctrl1.x);
-    left.ctrl2.y = left.ctrl1.y + at * (left.ctrl2.y - left.ctrl1.y);
-
-    left.end.x = cur.start.x = left.ctrl2.x + at * (cur.ctrl1.x - left.ctrl2.x);
-    left.end.y = cur.start.y = left.ctrl2.y + at * (cur.ctrl1.y - left.ctrl2.y);
-}
-
-
-static float _bezAt(const Bezier& bz, float at)
-{
-    auto len = _bezLength(bz);
-    auto biggest = 1.0f;
-
-    if (at >= len) return 1.0f;
-
-    at *= 0.5f;
-
-    while (true) {
-        auto right = bz;
-        Bezier left;
-        _bezSplitLeft(right, at, left);
-        auto len2 = _bezLength(left);
-
-        if (fabs(len2 - len) < FLT_EPSILON) break;
-
-        if (len2 < len) {
-            at += (biggest - at) * 0.5f;
-        } else {
-            biggest = at;
-            at -= (at * 0.5f);
-        }
-    }
-    return at;
-}
-
-
-static void _bezSplitAt(const Bezier& cur, float at, Bezier& left, Bezier& right)
-{
-    right = cur;
-    auto t = _bezAt(right, at);
-    _bezSplitLeft(right, t, left);
-}
-
-
 static void _growOutlineContour(SwOutline& outline, uint32_t n)
 {
     if (outline.reservedCntrsCnt >= outline.cntrsCnt + n) return;
@@ -407,7 +302,7 @@ static void _dashCubicTo(SwDashStroke& dash, const Point* ctrl1, const Point* ct
     _growOutlineContour(*dash.outline, dash.outline->cntrsCnt >> 1);
 
     Bezier cur = { dash.ptCur, *ctrl1, *ctrl2, *to};
-    auto len = _bezLength(cur);
+    auto len = bezLength(cur);
 
     if (len < dash.curLen) {
         dash.curLen -= len;
@@ -419,7 +314,7 @@ static void _dashCubicTo(SwDashStroke& dash, const Point* ctrl1, const Point* ct
         while (len > dash.curLen) {
             Bezier left, right;
             len -= dash.curLen;
-            _bezSplitAt(cur, dash.curLen, left, right);
+            bezSplitAt(cur, dash.curLen, left, right);
             dash.curIdx = (dash.curIdx + 1) % dash.cnt;
             if (!dash.curOpGap) {
                 _outlineMoveTo(*dash.outline, &left.start);

src/lib/tvgBezier.cpp

@@ -0,0 +1,144 @@
+/*
+ * Copyright (c) 2020 Samsung Electronics Co., Ltd All Rights Reserved
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *               http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+#ifndef _TVG_BEZIER_CPP_
+#define _TVG_BEZIER_CPP_
+
+#include "tvgCommon.h"
+
+
+/************************************************************************/
+/* Internal Class Implementation                                        */
+/************************************************************************/
+
+static float _lineLength(const Point& pt1, const Point& pt2)
+{
+    /* approximate sqrt(x*x + y*y) using alpha max plus beta min algorithm.
+       With alpha = 1, beta = 3/8, giving results with the largest error less
+       than 7% compared to the exact value. */
+    Point diff = {pt2.x - pt1.x, pt2.y - pt1.y};
+    if (diff.x < 0) diff.x = -diff.x;
+    if (diff.y < 0) diff.y = -diff.y;
+    return (diff.x > diff.y) ? (diff.x + diff.y * 0.375f) : (diff.y + diff.x * 0.375f);
+}
+
+
+/************************************************************************/
+/* External Class Implementation                                        */
+/************************************************************************/
+
+namespace tvg
+{
+
+void bezSplit(const Bezier&cur, Bezier& left, Bezier& right)
+{
+    auto c = (cur.ctrl1.x + cur.ctrl2.x) * 0.5f;
+    left.ctrl1.x = (cur.start.x + cur.ctrl1.x) * 0.5f;
+    right.ctrl2.x = (cur.ctrl2.x + cur.end.x) * 0.5f;
+    left.start.x = cur.start.x;
+    right.end.x = cur.end.x;
+    left.ctrl2.x = (left.ctrl1.x + c) * 0.5f;
+    right.ctrl1.x = (right.ctrl2.x + c) * 0.5f;
+    left.end.x = right.start.x = (left.ctrl2.x + right.ctrl1.x) * 0.5f;
+
+    c = (cur.ctrl1.y + cur.ctrl2.y) * 0.5f;
+    left.ctrl1.y = (cur.start.y + cur.ctrl1.y) * 0.5f;
+    right.ctrl2.y = (cur.ctrl2.y + cur.end.y) * 0.5f;
+    left.start.y = cur.start.y;
+    right.end.y = cur.end.y;
+    left.ctrl2.y = (left.ctrl1.y + c) * 0.5f;
+    right.ctrl1.y = (right.ctrl2.y + c) * 0.5f;
+    left.end.y = right.start.y = (left.ctrl2.y + right.ctrl1.y) * 0.5f;
+}
+
+
+float bezLength(const Bezier& cur)
+{
+    Bezier left, right;
+    auto len = _lineLength(cur.start, cur.ctrl1) + _lineLength(cur.ctrl1, cur.ctrl2) + _lineLength(cur.ctrl2, cur.end);
+    auto chord = _lineLength(cur.start, cur.end);
+
+    if (fabs(len - chord) > FLT_EPSILON) {
+        bezSplit(cur, left, right);
+        return bezLength(left) + bezLength(right);
+    }
+    return len;
+}
+
+
+void bezSplitLeft(Bezier& cur, float at, Bezier& left)
+{
+    left.start = cur.start;
+
+    left.ctrl1.x = cur.start.x + at * (cur.ctrl1.x - cur.start.x);
+    left.ctrl1.y = cur.start.y + at * (cur.ctrl1.y - cur.start.y);
+
+    left.ctrl2.x = cur.ctrl1.x + at * (cur.ctrl2.x - cur.ctrl1.x); // temporary holding spot
+    left.ctrl2.y = cur.ctrl1.y + at * (cur.ctrl2.y - cur.ctrl1.y); // temporary holding spot
+
+    cur.ctrl2.x = cur.ctrl2.x + at * (cur.end.x - cur.ctrl2.x);
+    cur.ctrl2.y = cur.ctrl2.y + at * (cur.end.y - cur.ctrl2.y);
+
+    cur.ctrl1.x = left.ctrl2.x + at * (cur.ctrl2.x - left.ctrl2.x);
+    cur.ctrl1.y = left.ctrl2.y + at * (cur.ctrl2.y - left.ctrl2.y);
+
+    left.ctrl2.x = left.ctrl1.x + at * (left.ctrl2.x - left.ctrl1.x);
+    left.ctrl2.y = left.ctrl1.y + at * (left.ctrl2.y - left.ctrl1.y);
+
+    left.end.x = cur.start.x = left.ctrl2.x + at * (cur.ctrl1.x - left.ctrl2.x);
+    left.end.y = cur.start.y = left.ctrl2.y + at * (cur.ctrl1.y - left.ctrl2.y);
+}
+
+
+float bezAt(const Bezier& bz, float at)
+{
+    auto len = bezLength(bz);
+    auto biggest = 1.0f;
+
+    if (at >= len) return 1.0f;
+
+    at *= 0.5f;
+
+    while (true) {
+        auto right = bz;
+        Bezier left;
+        bezSplitLeft(right, at, left);
+        auto len2 = bezLength(left);
+
+        if (fabs(len2 - len) < FLT_EPSILON) break;
+
+        if (len2 < len) {
+            at += (biggest - at) * 0.5f;
+        } else {
+            biggest = at;
+            at -= (at * 0.5f);
+        }
+    }
+    return at;
+}
+
+
+void bezSplitAt(const Bezier& cur, float at, Bezier& left, Bezier& right)
+{
+    right = cur;
+    auto t = bezAt(right, at);
+    bezSplitLeft(right, t, left);
+}
+
+
+}
+
+#endif //_TVG_BEZIER_CPP_

src/lib/tvgBezier.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2020 Samsung Electronics Co., Ltd All Rights Reserved
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *               http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+#ifndef _TVG_BEZIER_H_
+#define _TVG_BEZIER_H_
+
+namespace tvg
+{
+
+struct Bezier
+{
+    Point start;
+    Point ctrl1;
+    Point ctrl2;
+    Point end;
+};
+
+void bezSplit(const Bezier&cur, Bezier& left, Bezier& right);
+float bezLength(const Bezier& cur);
+void bezSplitLeft(Bezier& cur, float at, Bezier& left);
+float bezAt(const Bezier& bz, float at);
+void bezSplitAt(const Bezier& cur, float at, Bezier& left, Bezier& right);
+
+}
+
+#endif //_TVG_BEZIER_H_

src/lib/tvgCommon.h

@@ -37,6 +37,7 @@ using namespace tvg;
 #define FILL_ID_LINEAR 0
 #define FILL_ID_RADIAL 1
 
+#include "tvgBezier.h"
 #include "tvgLoader.h"
 #include "tvgLoaderMgr.h"
 #include "tvgRender.h"

src/lib/tvgRender.cpp

@@ -18,8 +18,6 @@
 #define _TVG_RENDER_CPP_
 
 #include "tvgCommon.h"
-#include "tvgRender.h"
-
 
 /************************************************************************/
 /* Internal Class Implementation                                        */