Implement CGPath related C API (#676)

* Implement _CGPathCopyDescription API

* Add _CGPathParseString API

* Add _CGPathCreateRoundedRect

* Audit _CGPathParseString implementation

* Fix _CGPathParseString

Author: Kyle-Ye

Package.swift

@@ -392,6 +392,14 @@ extension Target {
         var swiftSettings = swiftSettings ?? []
         swiftSettings.append(.define("OPENRENDERBOX_RENDERBOX"))
         self.swiftSettings = swiftSettings
+
+        var cSettings = cSettings ?? []
+        cSettings.append(.define("OPENRENDERBOX_RENDERBOX"))
+        self.cSettings = cSettings
+
+        var cxxSettings = cxxSettings ?? []
+        cxxSettings.append(.define("OPENRENDERBOX_RENDERBOX"))
+        self.cxxSettings = cxxSettings
     }
 
     func addCoreUISettings() {

Sources/OpenSwiftUICore/Shape/Path.swift

@@ -12,11 +12,6 @@ package import OpenRenderBoxShims
 import OpenSwiftUI_SPI
 public import OpenCoreGraphicsShims
 
-#if canImport(CoreGraphics)
-@_silgen_name("__CGPathParseString")
-private func __CGPathParseString(_ path: CGMutablePath, _ utf8CString: UnsafePointer<CChar>) -> Bool
-#endif
-
 // MARK: - Path
 
 /// The outline of a 2D shape.
@@ -280,7 +275,7 @@ public struct Path: Equatable, LosslessStringConvertible, @unchecked Sendable {
         guard let str = nsString.utf8String else {
             return nil
         }
-        guard __CGPathParseString(mutablePath, str) else {
+        guard _CGPathParseString(mutablePath, str) else {
             return nil
         }
         storage = .path(PathBox(mutablePath))

Sources/OpenSwiftUI_SPI/Overlay/CoreGraphics/CGPath+OpenSwiftUI.h

@@ -0,0 +1,73 @@
+//
+//  CGPath+OpenSwiftUI.h
+//  OpenSwiftUI_SPI
+
+#ifndef CGPath_OpenSwiftUI_h
+#define CGPath_OpenSwiftUI_h
+
+#include "OpenSwiftUIBase.h"
+
+#if OPENSWIFTUI_TARGET_OS_DARWIN
+
+#include <Foundation/Foundation.h>
+#include <CoreGraphics/CoreGraphics.h>
+
+OPENSWIFTUI_ASSUME_NONNULL_BEGIN
+
+/// Parses a path string and appends the path elements to a mutable path.
+///
+/// The string format uses space-separated numbers followed by command characters:
+///
+/// | Command | Parameters | Description |
+/// |---------|------------|-------------|
+/// | `m` | x y | Move to point |
+/// | `l` | x y | Line to point |
+/// | `c` | cp1x cp1y cp2x cp2y x y | Cubic Bézier curve |
+/// | `q` | cpx cpy x y | Quadratic Bézier curve |
+/// | `t` | x y | Smooth quadratic curve (reflects previous control point) |
+/// | `v` | cp2x cp2y x y | Smooth cubic curve (uses last point as cp1) |
+/// | `y` | cp1x cp1y x y | Shorthand cubic (cp2 equals endpoint) |
+/// | `h` | (none) | Close subpath |
+/// | `re` | x y width height | Rectangle |
+///
+/// Whitespace characters (space, tab, newline, carriage return) are skipped.
+/// Numbers can be integers, decimals, or special values like `Inf`.
+///
+/// - Parameters:
+///   - path: The mutable path to append elements to.
+///   - utf8CString: The path string to parse.
+/// - Returns: `YES` if parsing succeeded, `NO` if the string is malformed.
+BOOL _CGPathParseString(CGMutablePathRef path, const char *utf8CString);
+
+/// Creates a string description of a path with optional coordinate rounding.
+///
+/// - Parameters:
+///   - path: The path to describe.
+///   - step: The rounding step for coordinates. When non-zero, coordinates
+///     are rounded to the nearest multiple of this value. Pass 0 for no rounding.
+/// - Returns: A string representation of the path using SVG-like commands
+///   (m for move, l for line, h for close).
+NSString * _CGPathCopyDescription(CGPathRef path, CGFloat step);
+
+/// Creates a rounded rectangle path with the specified corner radii.
+///
+/// The corner radii are automatically clamped to fit within the rectangle:
+/// - Negative values are treated as 0
+/// - Values exceeding half the width or height are reduced accordingly
+///
+/// - Parameters:
+///   - rect: The rectangle to create the path from.
+///   - cornerWidth: The horizontal radius of the rounded corners.
+///   - cornerHeight: The vertical radius of the rounded corners.
+///   - useRB: If `YES`, uses RenderBox for path creation (when available).
+///     If `NO`, uses CoreGraphics directly.
+/// - Returns: A new path representing the rounded rectangle. Returns a plain
+///   rectangle path if either corner dimension is 0 or if the rect is empty.
+CF_RETURNS_RETAINED
+CGPathRef _CGPathCreateRoundedRect(CGRect rect, CGFloat cornerWidth, CGFloat cornerHeight, BOOL useRB);
+
+OPENSWIFTUI_ASSUME_NONNULL_END
+
+#endif
+
+#endif /* CGPath_OpenSwiftUI_h */

Sources/OpenSwiftUI_SPI/Overlay/CoreGraphics/CGPath+OpenSwiftUI.m

@@ -0,0 +1,269 @@
+//
+//  CGPath+OpenSwiftUI.m
+//  OpenSwiftUI_SPI
+
+#import "CGPath+OpenSwiftUI.h"
+
+#if OPENSWIFTUI_TARGET_OS_DARWIN
+
+#import <Foundation/Foundation.h>
+#import <CoreGraphics/CoreGraphics.h>
+#import <xlocale.h>
+
+#if OPENRENDERBOX_RENDERBOX
+@import RenderBox;
+#else
+@import OpenRenderBox;
+#endif
+
+BOOL _CGPathParseString(CGMutablePathRef path, const char *utf8CString) {
+    double numbers[6];
+    int numCount = 0;
+    CGFloat currentX = 0.0, currentY = 0.0;
+    CGFloat lastControlX = 0.0, lastControlY = 0.0;
+    const char *ptr = utf8CString;
+    do {
+        while (*ptr <= 0x1f) {
+            switch (*ptr) {
+            case 0: return true;
+            case 9: case 10: case 12: case 13: ptr++; break;
+            default: return false;
+            }
+        }
+        unsigned char c = (unsigned char)*ptr;
+        BOOL isNumberStart = NO;
+        switch (c) {
+            case ' ': break;
+            case '+': case '-': case '.': case '0' ... '9':
+            case 'E': case 'P': case 'X': case 'e': case 'p': case 'x':
+                isNumberStart = YES;
+                break;
+            case 'I':
+                if (ptr[1] == 'n' && ptr[2] == 'f') { isNumberStart = YES; }
+                break;
+            case 'm':
+                if (numCount != 2) return NO;
+                CGPathMoveToPoint(path, NULL,
+                                  numbers[0], numbers[1]);
+                currentX = lastControlX = numbers[0];
+                currentY = lastControlY = numbers[1];
+                numCount = 0;
+                break;
+            case 'l':
+                if (numCount != 2) return NO;
+                CGPathAddLineToPoint(path, NULL,
+                                     numbers[0], numbers[1]);
+                currentX = lastControlX = numbers[0];
+                currentY = lastControlY = numbers[1];
+                numCount = 0;
+                break;
+            case 'c':
+                if (numCount != 6) return NO;
+                CGPathAddCurveToPoint(path, NULL,
+                                      numbers[0], numbers[1],
+                                      numbers[2], numbers[3],
+                                      numbers[4], numbers[5]);
+                lastControlX = numbers[2];
+                lastControlY = numbers[3];
+                currentX = numbers[4];
+                currentY = numbers[5];
+                numCount = 0;
+                break;
+            case 'q':
+                if (numCount != 4) return NO;
+                CGPathAddQuadCurveToPoint(path, NULL,
+                                          numbers[0], numbers[1],
+                                          numbers[2], numbers[3]);
+                lastControlX = numbers[0];
+                lastControlY = numbers[1];
+                currentX = numbers[2];
+                currentY = numbers[3];
+                numCount = 0;
+                break;
+            case 't':
+                if (numCount != 2) return NO;
+                CGFloat reflectedX = currentX * 2.0 - lastControlX;
+                CGFloat reflectedY = currentY * 2.0 - lastControlY;
+                CGPathAddQuadCurveToPoint(path, NULL,
+                                            reflectedX, reflectedY,
+                                            numbers[0], numbers[1]);
+                lastControlX = reflectedX;
+                lastControlY = reflectedY;
+                currentX = numbers[0];
+                currentY = numbers[1];
+                numCount = 0;
+                break;
+            case 'v':
+                if (numCount != 4) return NO;
+                CGPathAddCurveToPoint(path, NULL,
+                                      currentX, currentY,
+                                      numbers[0], numbers[1],
+                                      numbers[2], numbers[3]);
+                lastControlX = numbers[0];
+                lastControlY = numbers[1];
+                currentX = numbers[2];
+                currentY = numbers[3];
+                numCount = 0;
+                break;
+            case 'y':
+                if (numCount != 4) return NO;
+                CGPathAddCurveToPoint(path, NULL,
+                                      numbers[0], numbers[1],
+                                      numbers[2], numbers[3],
+                                      numbers[2], numbers[3]);
+                lastControlX = numbers[2];
+                lastControlY = numbers[3];
+                numCount = 0;
+                break;
+            case 'h':
+                if (numCount != 0) return NO;
+                CGPathCloseSubpath(path);
+                lastControlX = 0.0;
+                lastControlY = 0.0;
+                numCount = 0;
+                break;
+            case 'r':
+                if (ptr[1] != 'e') return NO;
+                if (numCount != 4) return NO;
+                CGPathAddRect(path, NULL,
+                              CGRectMake(numbers[0], numbers[1],
+                                         numbers[2], numbers[3]));
+                ptr++;
+                numCount = 0;
+                break;
+            default:
+                return false;
+        }
+        if (isNumberStart) {
+            if (numCount == 6) return false;
+            char *endPtr;
+            numbers[numCount++] = strtod_l(ptr, &endPtr, NULL);
+            ptr = endPtr;
+        } else {
+            ptr++;
+        }
+    } while (1);
+}
+
+typedef struct PathInfo {
+    CFMutableStringRef description;
+    CGFloat step;
+    CGFloat inverseStep;
+} PathInfo;
+
+#define APPEND_COORD(coord) do { \
+    CGFloat value = (coord); \
+    if (path_info->step != 0.0) { \
+        value = path_info->step * round(value * path_info->inverseStep); \
+    } \
+    char buffer[64]; \
+    snprintf_l(buffer, 64, NULL, "%g ", value); \
+    CFStringAppendCString(path_info->description, buffer, kCFStringEncodingUTF8); \
+} while (0)
+
+#define APPEND_POINTS(count) do { \
+    for (int i = 0; i < (count); i++) { \
+        APPEND_COORD(element->points[i].x); \
+        APPEND_COORD(element->points[i].y); \
+    } \
+} while (0)
+
+void copy_path_iter(void * __nullable info, const CGPathElement * element) {
+    PathInfo *path_info = (PathInfo *)info;
+    if (path_info->description != NULL) {
+        CFStringAppend(path_info->description, CFSTR(" "));
+    }
+    UniChar ch;
+    switch (element->type) {
+        case kCGPathElementMoveToPoint:
+            APPEND_POINTS(1);
+            ch = 'm';
+            break;
+        case kCGPathElementAddLineToPoint:
+            APPEND_POINTS(1);
+            ch = 'l';
+            break;
+        case kCGPathElementAddQuadCurveToPoint:
+            APPEND_POINTS(2);
+            ch = 'q';
+            break;
+        case kCGPathElementAddCurveToPoint:
+            APPEND_POINTS(3);
+            ch = 'c';
+            break;
+        case kCGPathElementCloseSubpath:
+            ch = 'h';
+            break;
+        default:
+            return;
+    }
+    CFStringAppendCharacters(path_info->description, &ch, 1);
+}
+
+#undef APPEND_COORD
+#undef APPEND_POINTS
+
+NSString * _CGPathCopyDescription(CGPathRef path, CGFloat step) {
+    PathInfo info = {
+        CFStringCreateMutable(kCFAllocatorDefault, 0),
+        step,
+        1.0 / step
+    };
+    CGPathApply(path, &info, &copy_path_iter);
+    return (__bridge_transfer NSString *)(info.description);
+}
+
+CGPathRef _CGPathCreateRoundedRect(CGRect rect, CGFloat cornerWidth, CGFloat cornerHeight, BOOL useRB) {
+    // Clamp corner dimensions to be non-negative
+    if (cornerWidth < 0.0) {
+        cornerWidth = 0.0;
+    }
+    if (cornerHeight < 0.0) {
+        cornerHeight = 0.0;
+    }
+
+    // If either corner dimension is 0, or rect is empty, return a plain rectangle
+    if (cornerWidth == 0.0 || cornerHeight == 0.0 || CGRectIsEmpty(rect)) {
+        return CGPathCreateWithRect(rect, NULL);
+    }
+
+    if (useRB) {
+        #if OPENRENDERBOX_RENDERBOX
+        // RBPath rbPath = RBPathMakeRoundedRect(NULL, rect, cornerWidth, cornerHeight, YES);
+        // CGPathRef cgPath = RBPathCopyCGPath(rbPath);
+        // RBPathRelease(rbPath);
+        // return cgPath;
+        #else
+        // ORBPath rbPath = ORBPathMakeRoundedRect(NULL, rect, cornerWidth, cornerHeight, YES);
+        // CGPathRef cgPath = ORBPathCopyCGPath(rbPath);
+        // ORBPathRelease(rbPath);
+        // return cgPath;
+        #endif
+    }
+
+    // Use CoreGraphics path creation
+    CGFloat width = CGRectGetWidth(rect);
+    CGFloat height = CGRectGetHeight(rect);
+
+    // Clamp cornerWidth to at most half the width
+    if (cornerWidth * 2.0 > width) {
+        cornerWidth = nextafter(width * 0.5, 0.0);
+    }
+
+    // Clamp cornerHeight to at most half the height
+    if (cornerHeight * 2.0 > height) {
+        cornerHeight = nextafter(height * 0.5, 0.0);
+    }
+
+    // Final validation
+    if (cornerWidth < 0.0 || cornerWidth * 2.0 > width) {
+        return CGPathCreateWithRect(rect, NULL);
+    }
+    if (cornerHeight < 0.0 || cornerHeight * 2.0 > height) {
+        return CGPathCreateWithRect(rect, NULL);
+    }
+
+    return CGPathCreateWithRoundedRect(rect, cornerWidth, cornerHeight, NULL);
+}
+
+#endif