add SkParsePath to go to/from SVG strings (e.g. "M0,0 L10,20")
git-svn-id: http://skia.googlecode.com/svn/trunk@203 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/utils/SkParsePath.cpp b/src/utils/SkParsePath.cpp
new file mode 100644
index 0000000..df98436
--- /dev/null
+++ b/src/utils/SkParsePath.cpp
@@ -0,0 +1,232 @@
+#include "SkParse.h"
+#include "SkParsePath.h"
+
+static inline bool is_between(int c, int min, int max) {
+ return (unsigned)(c - min) <= (unsigned)(max - min);
+}
+
+static inline bool is_ws(int c) {
+ return is_between(c, 1, 32);
+}
+
+static inline bool is_digit(int c) {
+ return is_between(c, '0', '9');
+}
+
+static inline bool is_sep(int c) {
+ return is_ws(c) || c == ',';
+}
+
+static inline bool is_lower(int c) {
+ return is_between(c, 'a', 'z');
+}
+
+static inline int to_upper(int c) {
+ return c - 'a' + 'A';
+}
+
+static const char* skip_ws(const char str[]) {
+ SkASSERT(str);
+ while (is_ws(*str))
+ str++;
+ return str;
+}
+
+static const char* skip_sep(const char str[]) {
+ SkASSERT(str);
+ while (is_sep(*str))
+ str++;
+ return str;
+}
+
+static const char* find_points(const char str[], SkPoint value[], int count,
+ bool isRelative, SkPoint* relative) {
+ str = SkParse::FindScalars(str, &value[0].fX, count * 2);
+ if (isRelative) {
+ for (int index = 0; index < count; index++) {
+ value[index].fX += relative->fX;
+ value[index].fY += relative->fY;
+ }
+ }
+ return str;
+}
+
+static const char* find_scalar(const char str[], SkScalar* value,
+ bool isRelative, SkScalar relative) {
+ str = SkParse::FindScalar(str, value);
+ if (isRelative) {
+ *value += relative;
+ }
+ return str;
+}
+
+bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
+ SkPath path;
+ SkPoint f = {0, 0};
+ SkPoint c = {0, 0};
+ SkPoint lastc = {0, 0};
+ SkPoint points[3];
+ char op = '\0';
+ char previousOp = '\0';
+ bool relative = false;
+ for (;;) {
+ data = skip_ws(data);
+ if (data[0] == '\0') {
+ break;
+ }
+ char ch = data[0];
+ if (is_digit(ch) || ch == '-' || ch == '+') {
+ if (op == '\0') {
+ return false;
+ }
+ } else {
+ op = ch;
+ relative = false;
+ if (is_lower(op)) {
+ op = (char) to_upper(op);
+ relative = true;
+ }
+ data++;
+ data = skip_sep(data);
+ }
+ switch (op) {
+ case 'M':
+ data = find_points(data, points, 1, relative, &c);
+ path.moveTo(points[0]);
+ op = 'L';
+ c = points[0];
+ break;
+ case 'L':
+ data = find_points(data, points, 1, relative, &c);
+ path.lineTo(points[0]);
+ c = points[0];
+ break;
+ case 'H': {
+ SkScalar x;
+ data = find_scalar(data, &x, relative, c.fX);
+ path.lineTo(x, c.fY);
+ c.fX = x;
+ } break;
+ case 'V': {
+ SkScalar y;
+ data = find_scalar(data, &y, relative, c.fY);
+ path.lineTo(c.fX, y);
+ c.fY = y;
+ } break;
+ case 'C':
+ data = find_points(data, points, 3, relative, &c);
+ goto cubicCommon;
+ case 'S':
+ data = find_points(data, &points[1], 2, relative, &c);
+ points[0] = c;
+ if (previousOp == 'C' || previousOp == 'S') {
+ points[0].fX -= lastc.fX - c.fX;
+ points[0].fY -= lastc.fY - c.fY;
+ }
+ cubicCommon:
+ path.cubicTo(points[0], points[1], points[2]);
+ lastc = points[1];
+ c = points[2];
+ break;
+ case 'Q': // Quadratic Bezier Curve
+ data = find_points(data, points, 2, relative, &c);
+ goto quadraticCommon;
+ case 'T':
+ data = find_points(data, &points[1], 1, relative, &c);
+ points[0] = points[1];
+ if (previousOp == 'Q' || previousOp == 'T') {
+ points[0].fX = c.fX * 2 - lastc.fX;
+ points[0].fY = c.fY * 2 - lastc.fY;
+ }
+ quadraticCommon:
+ path.quadTo(points[0], points[1]);
+ lastc = points[0];
+ c = points[1];
+ break;
+ case 'Z':
+ path.close();
+#if 0 // !!! still a bug?
+ if (fPath.isEmpty() && (f.fX != 0 || f.fY != 0)) {
+ c.fX -= SkScalar.Epsilon; // !!! enough?
+ fPath.moveTo(c);
+ fPath.lineTo(f);
+ fPath.close();
+ }
+#endif
+ c = f;
+ op = '\0';
+ break;
+ case '~': {
+ SkPoint args[2];
+ data = find_points(data, args, 2, false, NULL);
+ path.moveTo(args[0].fX, args[0].fY);
+ path.lineTo(args[1].fX, args[1].fY);
+ } break;
+ default:
+ return false;
+ }
+ if (previousOp == 0) {
+ f = c;
+ }
+ previousOp = op;
+ }
+ // we're good, go ahead and swap in the result
+ result->swap(path);
+ return true;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+#include "SkString.h"
+#include "SkStream.h"
+
+static void write_scalar(SkWStream* stream, SkScalar value) {
+ char buffer[SkStrAppendScalar_MaxSize];
+ char* stop = SkStrAppendScalar(buffer, value);
+ stream->write(buffer, stop - buffer);
+}
+
+static void append_scalars(SkWStream* stream, char verb, const SkScalar data[],
+ int count) {
+ stream->write(&verb, 1);
+ write_scalar(stream, data[0]);
+ for (int i = 1; i < count; i++) {
+ if (data[i] >= 0) {
+ // can skip the separater if data[i] is negative
+ stream->write(" ", 1);
+ }
+ write_scalar(stream, data[i]);
+ }
+}
+
+void SkParsePath::ToSVGString(const SkPath& path, SkString* str) {
+ SkDynamicMemoryWStream stream;
+
+ SkPath::Iter iter(path, false);
+ SkPoint pts[4];
+
+ for (;;) {
+ switch (iter.next(pts)) {
+ case SkPath::kMove_Verb:
+ append_scalars(&stream, 'M', &pts[0].fX, 2);
+ break;
+ case SkPath::kLine_Verb:
+ append_scalars(&stream, 'L', &pts[1].fX, 2);
+ break;
+ case SkPath::kQuad_Verb:
+ append_scalars(&stream, 'Q', &pts[1].fX, 4);
+ break;
+ case SkPath::kCubic_Verb:
+ append_scalars(&stream, 'C', &pts[1].fX, 6);
+ break;
+ case SkPath::kClose_Verb:
+ stream.write("Z", 1);
+ break;
+ case SkPath::kDone_Verb:
+ str->resize(stream.getOffset());
+ stream.copyTo(str->writable_str());
+ return;
+ }
+ }
+}
+