CGContext接口文档

/* CoreGraphics - CGContext.h
   Copyright (c) 2000-2012 Apple Inc.
   All rights reserved. */

#ifndef CGCONTEXT_H_
#define CGCONTEXT_H_

#include 
#include 
#include 

typedef struct CGContext *CGContextRef;

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

CF_IMPLICIT_BRIDGING_ENABLED

CF_ASSUME_NONNULL_BEGIN

/* Drawing modes for paths. */

typedef CF_ENUM (int32_t, CGPathDrawingMode) {
  kCGPathFill,
  kCGPathEOFill,
  kCGPathStroke,
  kCGPathFillStroke,
  kCGPathEOFillStroke
};

/* Drawing modes for text. */

typedef CF_ENUM (int32_t, CGTextDrawingMode) {
  kCGTextFill,
  kCGTextStroke,
  kCGTextFillStroke,
  kCGTextInvisible,
  kCGTextFillClip,
  kCGTextStrokeClip,
  kCGTextFillStrokeClip,
  kCGTextClip
};

/* Text encodings. */

typedef CF_ENUM (int32_t, CGTextEncoding) {
  kCGEncodingFontSpecific,
  kCGEncodingMacRoman
} CG_AVAILABLE_BUT_DEPRECATED(__MAC_10_0, __MAC_10_9, __IPHONE_2_0, __IPHONE_7_0);

/* Interpolation quality. */

typedef CF_ENUM (int32_t, CGInterpolationQuality) {
  kCGInterpolationDefault = 0,  /* Let the context decide. */
  kCGInterpolationNone = 1,     /* Never interpolate. */
  kCGInterpolationLow = 2,      /* Low quality, fast interpolation. */
  kCGInterpolationMedium = 4,   /* Medium quality, slower than kCGInterpolationLow. */
  kCGInterpolationHigh = 3      /* Highest quality, slower than kCGInterpolationMedium. */
};

/* Blend modes.

   The blend modes from kCGBlendModeNormal to kCGBlendModeLuminosity are
   supported in Mac OS X 10.4 and later. The Porter-Duff blend modes (from
   kCGBlendModeClear to kCGBlendModePlusLighter) are supported in Mac OS X
   10.5 and later. The names of the Porter-Duff blend modes are historical.

   Note that the Porter-Duff blend modes are not necessarily supported in
   every context. In particular, they are only guaranteed to work in
   bitmap-based contexts, such as those created by CGBitmapContextCreate. It
   is your responsibility to make sure that they do what you want when you
   use them in a CGContext. */

typedef CF_ENUM (int32_t, CGBlendMode) {
    /* Available in Mac OS X 10.4 & later. */
    kCGBlendModeNormal,
    kCGBlendModeMultiply,
    kCGBlendModeScreen,
    kCGBlendModeOverlay,
    kCGBlendModeDarken,
    kCGBlendModeLighten,
    kCGBlendModeColorDodge,
    kCGBlendModeColorBurn,
    kCGBlendModeSoftLight,
    kCGBlendModeHardLight,
    kCGBlendModeDifference,
    kCGBlendModeExclusion,
    kCGBlendModeHue,
    kCGBlendModeSaturation,
    kCGBlendModeColor,
    kCGBlendModeLuminosity,

    /* Available in Mac OS X 10.5 & later. R, S, and D are, respectively,
       premultiplied result, source, and destination colors with alpha; Ra,
       Sa, and Da are the alpha components of these colors.

       The Porter-Duff "source over" mode is called `kCGBlendModeNormal':
         R = S + D*(1 - Sa)

       Note that the Porter-Duff "XOR" mode is only titularly related to the
       classical bitmap XOR operation (which is unsupported by
       CoreGraphics). */

    kCGBlendModeClear,                  /* R = 0 */
    kCGBlendModeCopy,                   /* R = S */
    kCGBlendModeSourceIn,               /* R = S*Da */
    kCGBlendModeSourceOut,              /* R = S*(1 - Da) */
    kCGBlendModeSourceAtop,             /* R = S*Da + D*(1 - Sa) */
    kCGBlendModeDestinationOver,        /* R = S*(1 - Da) + D */
    kCGBlendModeDestinationIn,          /* R = D*Sa */
    kCGBlendModeDestinationOut,         /* R = D*(1 - Sa) */
    kCGBlendModeDestinationAtop,        /* R = S*(1 - Da) + D*Sa */
    kCGBlendModeXOR,                    /* R = S*(1 - Da) + D*(1 - Sa) */
    kCGBlendModePlusDarker,             /* R = MAX(0, (1 - D) + (1 - S)) */
    kCGBlendModePlusLighter             /* R = MIN(1, S + D) */
};

/* Return the CFTypeID for CGContextRefs. */

CG_EXTERN CFTypeID CGContextGetTypeID(void)
    CG_AVAILABLE_STARTING(__MAC_10_2, __IPHONE_2_0);

/** Graphics state functions. **/

/* Push a copy of the current graphics state onto the graphics state stack.
   Note that the path is not considered part of the graphics state, and is
   not saved. */

CG_EXTERN void CGContextSaveGState(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Restore the current graphics state from the one on the top of the
   graphics state stack, popping the graphics state stack in the process. */

CG_EXTERN void CGContextRestoreGState(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Coordinate space transformations. **/

/* Scale the current graphics state's transformation matrix (the CTM) by
   `(sx, sy)'. */

CG_EXTERN void CGContextScaleCTM(CGContextRef __nullable c,
    CGFloat sx, CGFloat sy)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Translate the current graphics state's transformation matrix (the CTM) by
   `(tx, ty)'. */

CG_EXTERN void CGContextTranslateCTM(CGContextRef __nullable c,
    CGFloat tx, CGFloat ty)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Rotate the current graphics state's transformation matrix (the CTM) by
   `angle' radians. */

CG_EXTERN void CGContextRotateCTM(CGContextRef __nullable c, CGFloat angle)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Concatenate the current graphics state's transformation matrix (the CTM)
   with the affine transform `transform'. */

CG_EXTERN void CGContextConcatCTM(CGContextRef __nullable c,
    CGAffineTransform transform)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the current graphics state's transformation matrix. Returns 
   CGAffineTransformIdentity in case of inavlid context. */

CG_EXTERN CGAffineTransform CGContextGetCTM(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Drawing attribute functions. **/

/* Set the line width in the current graphics state to `width'. */

CG_EXTERN void CGContextSetLineWidth(CGContextRef __nullable c, CGFloat width)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the line cap in the current graphics state to `cap'. */

CG_EXTERN void CGContextSetLineCap(CGContextRef __nullable c, CGLineCap cap)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the line join in the current graphics state to `join'. */

CG_EXTERN void CGContextSetLineJoin(CGContextRef __nullable c, CGLineJoin join)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the miter limit in the current graphics state to `limit'. */

CG_EXTERN void CGContextSetMiterLimit(CGContextRef __nullable c, CGFloat limit)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the line dash patttern in the current graphics state of `c'. */

CG_EXTERN void CGContextSetLineDash(CGContextRef __nullable c, CGFloat phase,
    const CGFloat * __nullable lengths, size_t count)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the path flatness parameter in the current graphics state of `c' to
   `flatness'. */

CG_EXTERN void CGContextSetFlatness(CGContextRef __nullable c, CGFloat flatness)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the alpha value in the current graphics state of `c' to `alpha'. */

CG_EXTERN void CGContextSetAlpha(CGContextRef __nullable c, CGFloat alpha)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the blend mode of `context' to `mode'. */

CG_EXTERN void CGContextSetBlendMode(CGContextRef __nullable c, CGBlendMode mode)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/** Path construction functions. **/

/* Note that a context has a single path in use at any time: a path is not
   part of the graphics state. */

/* Begin a new path. The old path is discarded. */

CG_EXTERN void CGContextBeginPath(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Start a new subpath at point `(x, y)' in the context's path. */

CG_EXTERN void CGContextMoveToPoint(CGContextRef __nullable c,
    CGFloat x, CGFloat y)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Append a straight line segment from the current point to `(x, y)'. */

CG_EXTERN void CGContextAddLineToPoint(CGContextRef __nullable c,
    CGFloat x, CGFloat y)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Append a cubic Bezier curve from the current point to `(x,y)', with
   control points `(cp1x, cp1y)' and `(cp2x, cp2y)'. */

CG_EXTERN void CGContextAddCurveToPoint(CGContextRef __nullable c, CGFloat cp1x,
    CGFloat cp1y, CGFloat cp2x, CGFloat cp2y, CGFloat x, CGFloat y)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Append a quadratic curve from the current point to `(x, y)', with control
   point `(cpx, cpy)'. */

CG_EXTERN void CGContextAddQuadCurveToPoint(CGContextRef __nullable c,
    CGFloat cpx, CGFloat cpy, CGFloat x, CGFloat y)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Close the current subpath of the context's path. */

CG_EXTERN void CGContextClosePath(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Path construction convenience functions. **/

/* Add a single rect to the context's path. */

CG_EXTERN void CGContextAddRect(CGContextRef __nullable c, CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Add a set of rects to the context's path. */

CG_EXTERN void CGContextAddRects(CGContextRef __nullable c,
    const CGRect * __nullable rects, size_t count)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Add a set of lines to the context's path. */

CG_EXTERN void CGContextAddLines(CGContextRef __nullable c,
    const CGPoint * __nullable points, size_t count)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Add an ellipse inside `rect' to the current path of `context'. See the
   function `CGPathAddEllipseInRect' for more information on how the path
   for the ellipse is constructed. */

CG_EXTERN void CGContextAddEllipseInRect(CGContextRef __nullable c, CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Add an arc of a circle to the context's path, possibly preceded by a
   straight line segment. `(x, y)' is the center of the arc; `radius' is its
   radius; `startAngle' is the angle to the first endpoint of the arc;
   `endAngle' is the angle to the second endpoint of the arc; and
   `clockwise' is 1 if the arc is to be drawn clockwise, 0 otherwise.
   `startAngle' and `endAngle' are measured in radians. */

CG_EXTERN void CGContextAddArc(CGContextRef __nullable c, CGFloat x, CGFloat y,
    CGFloat radius, CGFloat startAngle, CGFloat endAngle, int clockwise)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Add an arc of a circle to the context's path, possibly preceded by a
   straight line segment. `radius' is the radius of the arc. The arc is
   tangent to the line from the current point to `(x1, y1)', and the line
   from `(x1, y1)' to `(x2, y2)'. */

CG_EXTERN void CGContextAddArcToPoint(CGContextRef __nullable c,
    CGFloat x1, CGFloat y1, CGFloat x2, CGFloat y2, CGFloat radius)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Add `path' to the path of context. The points in `path' are transformed
   by the CTM of context before they are added. */

CG_EXTERN void CGContextAddPath(CGContextRef __nullable c,
    CGPathRef __nullable path)
    CG_AVAILABLE_STARTING(__MAC_10_2, __IPHONE_2_0);

/** Path stroking. **/

/* Replace the path in `context' with the stroked version of the path, using
   the parameters of `context' to calculate the stroked path. The resulting
   path is created such that filling it with the appropriate color will
   produce the same results as stroking the original path. You can use this
   path in the same way you can use the path of any context; for example,
   you can clip to the stroked version of a path by calling this function
   followed by a call to "CGContextClip". */

CG_EXTERN void CGContextReplacePathWithStrokedPath(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/** Path information functions. **/

/* Return true if the path of `context' contains no elements, false
   otherwise. */

CG_EXTERN bool CGContextIsPathEmpty(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the current point of the current subpath of the path of
   `context'. */

CG_EXTERN CGPoint CGContextGetPathCurrentPoint(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the bounding box of the path of `context'. The bounding box is the
   smallest rectangle completely enclosing all points in the path, including
   control points for Bezier and quadratic curves. */

CG_EXTERN CGRect CGContextGetPathBoundingBox(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return a copy of the path of `context'. The returned path is specified in
   the current user space of `context'. */

CG_EXTERN CGPathRef __nullable CGContextCopyPath(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_2, __IPHONE_2_0);

/* Return true if `point' is contained in the current path of `context'. A
   point is contained within a context's path if it is inside the painted
   region when the path is stroked or filled with opaque colors using the
   path drawing mode `mode'. `point' is specified is user space. */

CG_EXTERN bool CGContextPathContainsPoint(CGContextRef __nullable c,
    CGPoint point, CGPathDrawingMode mode)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/** Path drawing functions. **/

/* Draw the context's path using drawing mode `mode'. */

CG_EXTERN void CGContextDrawPath(CGContextRef __nullable c,
    CGPathDrawingMode mode)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Path drawing convenience functions. **/

/* Fill the context's path using the winding-number fill rule. Any open
   subpath of the path is implicitly closed. */

CG_EXTERN void CGContextFillPath(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Fill the context's path using the even-odd fill rule. Any open subpath of
   the path is implicitly closed. */

CG_EXTERN void CGContextEOFillPath(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Stroke the context's path. */

CG_EXTERN void CGContextStrokePath(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Fill `rect' with the current fill color. */

CG_EXTERN void CGContextFillRect(CGContextRef __nullable c, CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Fill `rects', an array of `count' CGRects, with the current fill
   color. */

CG_EXTERN void CGContextFillRects(CGContextRef __nullable c,
    const CGRect * __nullable rects, size_t count)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Stroke `rect' with the current stroke color and the current linewidth. */

CG_EXTERN void CGContextStrokeRect(CGContextRef __nullable c, CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Stroke `rect' with the current stroke color, using `width' as the the
   line width. */

CG_EXTERN void CGContextStrokeRectWithWidth(CGContextRef __nullable c,
    CGRect rect, CGFloat width)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Clear `rect' (that is, set the region within the rect to transparent). */

CG_EXTERN void CGContextClearRect(CGContextRef __nullable c, CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Fill an ellipse (an oval) inside `rect'. */

CG_EXTERN void CGContextFillEllipseInRect(CGContextRef __nullable c,
    CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Stroke an ellipse (an oval) inside `rect'. */

CG_EXTERN void CGContextStrokeEllipseInRect(CGContextRef __nullable c,
    CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Stroke a sequence of line segments one after another in `context'. The
   line segments are specified by `points', an array of `count' CGPoints.
   This function is equivalent to

     CGContextBeginPath(context);
     for (k = 0; k < count; k += 2) {
       CGContextMoveToPoint(context, s[k].x, s[k].y);
       CGContextAddLineToPoint(context, s[k+1].x, s[k+1].y);
     }
     CGContextStrokePath(context); */

CG_EXTERN void CGContextStrokeLineSegments(CGContextRef __nullable c,
    const CGPoint * __nullable points, size_t count)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/** Clipping functions. **/

/* Intersect the context's path with the current clip path and use the
   resulting path as the clip path for subsequent rendering operations. Use
   the winding-number fill rule for deciding what's inside the path. */

CG_EXTERN void CGContextClip(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Intersect the context's path with the current clip path and use the
   resulting path as the clip path for subsequent rendering operations. Use
   the even-odd fill rule for deciding what's inside the path. */

CG_EXTERN void CGContextEOClip(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Add `mask' transformed to `rect' to the clipping area of `context'. The
   mask, which may be either an image mask or an image, is mapped into the
   specified rectangle and intersected with the current clipping area of the
   context.

   If `mask' is an image mask, then it clips in a manner identical to the
   behavior if it were used with "CGContextDrawImage": it indicates an area
   to be masked out (left unchanged) when drawing. The source samples of the
   image mask determine which points of the clipping area are changed,
   acting as an "inverse alpha": if the value of a source sample in the
   image mask is S, then the corresponding point in the current clipping
   area will be multiplied by an alpha of (1-S). (For example, if S is 1,
   then the point in the clipping area becomes clear, while if S is 0, the
   point in the clipping area is unchanged.

   If `mask' is an image, then it serves as alpha mask and is blended with
   the current clipping area. The source samples of mask determine which
   points of the clipping area are changed: if the value of the source
   sample in mask is S, then the corresponding point in the current clipping
   area will be multiplied by an alpha of S. (For example, if S is 0, then
   the point in the clipping area becomes clear, while if S is 1, the point
   in the clipping area is unchanged.

   If `mask' is an image, then it must be in the DeviceGray color space, may
   not have alpha, and may not be masked by an image mask or masking
   color. */

CG_EXTERN void CGContextClipToMask(CGContextRef __nullable c, CGRect rect,
    CGImageRef __nullable mask)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Return the bounding box of the clip path of `c' in user space. The
   bounding box is the smallest rectangle completely enclosing all points in
   the clip. */

CG_EXTERN CGRect CGContextGetClipBoundingBox(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_3, __IPHONE_2_0);

/** Clipping convenience functions. **/

/* Intersect the current clipping path with `rect'. Note that this function
   resets the context's path to the empty path. */

CG_EXTERN void CGContextClipToRect(CGContextRef __nullable c, CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Intersect the current clipping path with the clipping region formed by
   creating a path consisting of all rects in `rects'. Note that this
   function resets the context's path to the empty path. */

CG_EXTERN void CGContextClipToRects(CGContextRef __nullable c,
    const CGRect *  rects, size_t count)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Primitive color functions. **/

/* Set the current fill color in the context `c' to `color'. */

CG_EXTERN void CGContextSetFillColorWithColor(CGContextRef __nullable c,
    CGColorRef __nullable color)
    CG_AVAILABLE_STARTING(__MAC_10_3, __IPHONE_2_0);

/* Set the current stroke color in the context `c' to `color'. */

CG_EXTERN void CGContextSetStrokeColorWithColor(CGContextRef __nullable c,
    CGColorRef __nullable color)
    CG_AVAILABLE_STARTING(__MAC_10_3, __IPHONE_2_0);

/** Color space functions. **/

/* Set the current fill color space in `context' to `space'. As a
   side-effect, set the fill color to a default value appropriate for the
   color space. */

CG_EXTERN void CGContextSetFillColorSpace(CGContextRef __nullable c,
    CGColorSpaceRef __nullable space)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the current stroke color space in `context' to `space'. As a
   side-effect, set the stroke color to a default value appropriate for the
   color space. */

CG_EXTERN void CGContextSetStrokeColorSpace(CGContextRef __nullable c,
    CGColorSpaceRef __nullable space)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Color functions. **/

/* Set the components of the current fill color in `context' to the values
   specifed by `components'. The number of elements in `components' must be
   one greater than the number of components in the current fill color space
   (N color components + 1 alpha component). The current fill color space
   must not be a pattern color space. */

CG_EXTERN void CGContextSetFillColor(CGContextRef __nullable c,
    const CGFloat * __nullable components)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the components of the current stroke color in `context' to the values
   specifed by `components'. The number of elements in `components' must be
   one greater than the number of components in the current stroke color
   space (N color components + 1 alpha component). The current stroke color
   space must not be a pattern color space. */

CG_EXTERN void CGContextSetStrokeColor(CGContextRef __nullable c,
    const CGFloat * __nullable components)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Pattern functions. **/

/* Set the components of the current fill color in `context' to the values
   specifed by `components', and set the current fill pattern to `pattern'.
   The number of elements in `components' must be one greater than the
   number of components in the current fill color space (N color components
   + 1 alpha component). The current fill color space must be a pattern
   color space. */

CG_EXTERN void CGContextSetFillPattern(CGContextRef __nullable c,
    CGPatternRef __nullable pattern, const CGFloat * __nullable components)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the components of the current stroke color in `context' to the values
   specifed by `components', and set the current stroke pattern to
   `pattern'. The number of elements in `components' must be one greater
   than the number of components in the current stroke color space (N color
   components + 1 alpha component). The current stroke color space must be a
   pattern color space. */

CG_EXTERN void CGContextSetStrokePattern(CGContextRef __nullable c,
    CGPatternRef __nullable pattern, const CGFloat * __nullable components)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the pattern phase in the current graphics state of `context' to
   `phase'. */

CG_EXTERN void CGContextSetPatternPhase(CGContextRef __nullable c, CGSize phase)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Color convenience functions. **/

/* Set the current fill color space in `context' to `DeviceGray' and set the
   components of the current fill color to `(gray, alpha)'. */

CG_EXTERN void CGContextSetGrayFillColor(CGContextRef __nullable c,
    CGFloat gray, CGFloat alpha)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the current stroke color space in `context' to `DeviceGray' and set
   the components of the current stroke color to `(gray, alpha)'. */

CG_EXTERN void CGContextSetGrayStrokeColor(CGContextRef __nullable c,
    CGFloat gray, CGFloat alpha)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the current fill color space in `context' to `DeviceRGB' and set the
   components of the current fill color to `(red, green, blue, alpha)'. */

CG_EXTERN void CGContextSetRGBFillColor(CGContextRef __nullable c, CGFloat red,
    CGFloat green, CGFloat blue, CGFloat alpha)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the current stroke color space in `context' to `DeviceRGB' and set
   the components of the current stroke color to `(red, green, blue,
   alpha)'. */

CG_EXTERN void CGContextSetRGBStrokeColor(CGContextRef __nullable c,
    CGFloat red, CGFloat green, CGFloat blue, CGFloat alpha)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the current fill color space in `context' to `DeviceCMYK' and set the
   components of the current fill color to `(cyan, magenta, yellow, black,
   alpha)'. */

CG_EXTERN void CGContextSetCMYKFillColor(CGContextRef __nullable c,
    CGFloat cyan, CGFloat magenta, CGFloat yellow, CGFloat black, CGFloat alpha)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the current stroke color space in `context' to `DeviceCMYK' and set
   the components of the current stroke color to `(cyan, magenta, yellow,
   black, alpha)'. */

CG_EXTERN void CGContextSetCMYKStrokeColor(CGContextRef __nullable c,
    CGFloat cyan, CGFloat magenta, CGFloat yellow, CGFloat black, CGFloat alpha)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Rendering intent. **/

/* Set the rendering intent in the current graphics state of `context' to
   `intent'. */

CG_EXTERN void CGContextSetRenderingIntent(CGContextRef __nullable c,
    CGColorRenderingIntent intent)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Image functions. **/

/* Draw `image' in the rectangular area specified by `rect' in the context
   `c'. The image is scaled, if necessary, to fit into `rect'. */

CG_EXTERN void CGContextDrawImage(CGContextRef __nullable c, CGRect rect,
    CGImageRef __nullable image)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Draw `image' tiled in the context `c'. The image is scaled to the size
   specified by `rect' in user space, positioned at the origin of `rect' in
   user space, then replicated, stepping the width of `rect' horizontally
   and the height of `rect' vertically, to fill the current clip region.
   Unlike patterns, the image is tiled in user space, so transformations
   applied to the CTM affect the final result. */

CG_EXTERN void CGContextDrawTiledImage(CGContextRef __nullable c, CGRect rect,
    CGImageRef __nullable image)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* Return the interpolation quality for image rendering of `context'. The
   interpolation quality is a gstate parameter which controls the level of
   interpolation performed when an image is interpolated (for example, when
   scaling the image). Note that it is merely a hint to the context: not all
   contexts support all interpolation quality levels. */

CG_EXTERN CGInterpolationQuality
    CGContextGetInterpolationQuality(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the interpolation quality of `context' to `quality'. */

CG_EXTERN void CGContextSetInterpolationQuality(CGContextRef __nullable c,
    CGInterpolationQuality quality)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Shadow support. **/

/* Set the shadow parameters in `context'. `offset' specifies a translation
   in base-space; `blur' is a non-negative number specifying the amount of
   blur; `color' specifies the color of the shadow, which may contain a
   non-opaque alpha value. If `color' is NULL, it's equivalent to specifying
   a fully transparent color. The shadow is a gstate parameter. After a
   shadow is specified, all objects drawn subsequently will be shadowed. To
   turn off shadowing, set the shadow color to a fully transparent color (or
   pass NULL as the color), or use the standard gsave/grestore mechanism. */

CG_EXTERN void CGContextSetShadowWithColor(CGContextRef __nullable c,
    CGSize offset, CGFloat blur, CGColorRef __nullable color)
    CG_AVAILABLE_STARTING(__MAC_10_3, __IPHONE_2_0);

/* Equivalent to calling
     CGContextSetShadowWithColor(context, offset, blur, color)
   where color is black with 1/3 alpha (i.e., RGBA = {0, 0, 0, 1.0/3.0}) in
   the DeviceRGB color space. */

CG_EXTERN void CGContextSetShadow(CGContextRef __nullable c, CGSize offset,
    CGFloat blur)
    CG_AVAILABLE_STARTING(__MAC_10_3, __IPHONE_2_0);

/** Gradient and shading functions. **/

/* Fill the current clipping region of `context' with a linear gradient from
   `startPoint' to `endPoint'. The location 0 of `gradient' corresponds to
   `startPoint'; the location 1 of `gradient' corresponds to `endPoint';
   colors are linearly interpolated between these two points based on the
   values of the gradient's locations. The option flags control whether the
   gradient is drawn before the start point or after the end point. */

CG_EXTERN void CGContextDrawLinearGradient(CGContextRef __nullable c,
    CGGradientRef __nullable gradient, CGPoint startPoint, CGPoint endPoint,
    CGGradientDrawingOptions options)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* Fill the current clipping region of `context' with a radial gradient
   between two circles defined by the center point and radius of each
   circle. The location 0 of `gradient' corresponds to a circle centered at
   `startCenter' with radius `startRadius'; the location 1 of `gradient'
   corresponds to a circle centered at `endCenter' with radius `endRadius';
   colors are linearly interpolated between these two circles based on the
   values of the gradient's locations. The option flags control whether the
   gradient is drawn before the start circle or after the end circle. */

CG_EXTERN void CGContextDrawRadialGradient(CGContextRef __nullable c,
    CGGradientRef __nullable gradient, CGPoint startCenter, CGFloat startRadius,
    CGPoint endCenter, CGFloat endRadius, CGGradientDrawingOptions options)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* Fill the current clipping region of `context' with `shading'. */

CG_EXTERN void CGContextDrawShading(CGContextRef __nullable c,
    __nullable CGShadingRef shading)
    CG_AVAILABLE_STARTING(__MAC_10_2, __IPHONE_2_0);

/** Text functions. **/

/* Set the current character spacing in `context' to `spacing'. The
   character spacing is added to the displacement between the origin of one
   character and the origin of the next. */

CG_EXTERN void CGContextSetCharacterSpacing(CGContextRef __nullable c,
    CGFloat spacing)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the user-space point at which text will be drawn in the context `c'
   to `(x, y)'. */

CG_EXTERN void CGContextSetTextPosition(CGContextRef __nullable c,
    CGFloat x, CGFloat y)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the user-space point at which text will be drawn in `context'. */

CG_EXTERN CGPoint CGContextGetTextPosition(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the text matrix in the context `c' to `t'. */

CG_EXTERN void CGContextSetTextMatrix(CGContextRef __nullable c,
    CGAffineTransform t)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the text matrix in the context `c'. Returns CGAffineTransformIdentity
   if `c' is not a valid context. */

CG_EXTERN CGAffineTransform CGContextGetTextMatrix(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the text drawing mode in the current graphics state of the context
   `c' to `mode'. */

CG_EXTERN void CGContextSetTextDrawingMode(CGContextRef __nullable c,
    CGTextDrawingMode mode)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the font in the current graphics state of the context `c' to
   `font'. */

CG_EXTERN void CGContextSetFont(CGContextRef __nullable c,
    CGFontRef __nullable font)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Set the font size in the current graphics state of the context `c' to
   `size'. */

CG_EXTERN void CGContextSetFontSize(CGContextRef __nullable c, CGFloat size)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Draw `glyphs', an array of `count' CGGlyphs, at the points specified by
   `positions'. Each element of `positions' specifies the position from the
   associated glyph; the positions are specified in user space. */

CG_EXTERN void CGContextShowGlyphsAtPositions(CGContextRef __nullable c,
    const CGGlyph * __nullable glyphs, const CGPoint * __nullable Lpositions,
    size_t count)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/** PDF functions. **/

/* Draw `page' in the current user space of the context `c'. */

CG_EXTERN void CGContextDrawPDFPage(CGContextRef __nullable c,
    CGPDFPageRef __nullable page)
    CG_AVAILABLE_STARTING(__MAC_10_3, __IPHONE_2_0);

/** Output page functions. **/

/* Begin a new page. */

CG_EXTERN void CGContextBeginPage(CGContextRef __nullable c,
    const CGRect * __nullable mediaBox)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* End the current page. */

CG_EXTERN void CGContextEndPage(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Context functions. **/

/* Equivalent to `CFRetain(c)'. */

CG_EXTERN CGContextRef __nullable CGContextRetain(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Equivalent to `CFRelease(c)'. */

CG_EXTERN void CGContextRelease(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Flush all drawing to the destination. */

CG_EXTERN void CGContextFlush(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Synchronized drawing. */

CG_EXTERN void CGContextSynchronize(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/** Antialiasing functions. **/

/* Turn on antialiasing if `shouldAntialias' is true; turn it off otherwise.
   This parameter is part of the graphics state. */

CG_EXTERN void CGContextSetShouldAntialias(CGContextRef __nullable c,
    bool shouldAntialias)
    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Allow antialiasing in `context' if `allowsAntialiasing' is true; don't
   allow it otherwise. This parameter is not part of the graphics state. A
   context will perform antialiasing if both `allowsAntialiasing' and the
   graphics state parameter `shouldAntialias' are true. */

CG_EXTERN void CGContextSetAllowsAntialiasing(CGContextRef __nullable c,
    bool allowsAntialiasing)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/** Font display functions. **/

/* Turn on font smoothing if `shouldSmoothFonts' is true; turn it off
   otherwise. This parameter is part of the graphics state. Note that this
   doesn't guarantee that font smoothing will occur: not all destination
   contexts support font smoothing. */

CG_EXTERN void CGContextSetShouldSmoothFonts(CGContextRef __nullable c,
    bool shouldSmoothFonts)
    CG_AVAILABLE_STARTING(__MAC_10_2, __IPHONE_2_0);

/* If `allowsFontSmoothing' is true, then allow font smoothing when
   displaying text in `context'; otherwise, don't allow font smoothing. This
   parameter is not part of the graphics state. Fonts will be smoothed if
   they are antialiased when drawn and if both `allowsFontSmoothing' and the
   graphics state parameter `shouldSmoothFonts' are true. */
 
CG_EXTERN void CGContextSetAllowsFontSmoothing(CGContextRef __nullable c,
    bool allowsFontSmoothing)
    CG_AVAILABLE_STARTING(__MAC_10_2, __IPHONE_2_0);

/* If `shouldSubpixelPositionFonts' is true, then glyphs may be placed at
   subpixel positions (if allowed) when displaying text in `context';
   otherwise, glyphs will be forced to integer pixel boundaries. This
   parameter is part of the graphics state. */

CG_EXTERN void CGContextSetShouldSubpixelPositionFonts(
    CGContextRef __nullable c, bool shouldSubpixelPositionFonts)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* If `allowsFontSubpixelPositioning' is true, then allow font subpixel
   positioning when displaying text in `context'; otherwise, don't allow
   subpixel positioning. This parameter is not part of the graphics state. A
   context will place glyphs at subpixel positions if fonts will be
   antialiased when drawn and if both `allowsFontSubpixelPositioning' and
   the graphics state parameter `shouldSubpixelPositionFonts' are true. */

CG_EXTERN void CGContextSetAllowsFontSubpixelPositioning(
    CGContextRef __nullable c, bool allowsFontSubpixelPositioning)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* If `shouldSubpixelQuantizeFonts' is true, then quantize the subpixel
   positions of glyphs when displaying text in `context'; otherwise, don't
   quantize the subpixel positions. This parameter is part of the graphics
   state. */

CG_EXTERN void CGContextSetShouldSubpixelQuantizeFonts(
    CGContextRef __nullable c, bool shouldSubpixelQuantizeFonts)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* If `allowsFontSubpixelQuantization' is true, then allow font subpixel
   quantization when displaying text in `context'; otherwise, don't allow
   subpixel quantization. This parameter is not part of the graphics state.
   A context quantizes subpixel positions if glyphs will be drawn at
   subpixel positions and `allowsFontSubpixelQuantization' and the graphics
   state parameter `shouldSubpixelQuantizeFonts' are both true. */

CG_EXTERN void CGContextSetAllowsFontSubpixelQuantization(
    CGContextRef __nullable c, bool allowsFontSubpixelQuantization)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/** Transparency layer support. **/

/* Begin a transparency layer in `context'. All subsequent drawing
   operations until a corresponding `CGContextEndTransparencyLayer' are
   composited into a fully transparent backdrop (which is treated as a
   separate destination buffer from the context). After the transparency
   layer is ended, the result is composited into the context using the
   global alpha and shadow state of the context. This operation respects the
   clipping region of the context. After a call to this function, all of the
   parameters in the graphics state remain unchanged with the exception of
   the following:
     - The global alpha is set to 1.
     - The shadow is turned off.
     - The blend mode is set to `kCGBlendModeNormal'.
   Ending the transparency layer restores these parameters to the values
   they had before `CGContextBeginTransparencyLayer' was called.
   Transparency layers may be nested. */

CG_EXTERN void CGContextBeginTransparencyLayer(CGContextRef __nullable c,
    CFDictionaryRef __nullable auxiliaryInfo)
    CG_AVAILABLE_STARTING(__MAC_10_3, __IPHONE_2_0);

/* Begin a transparency layer in `context'. This function is identical to
  `CGContextBeginTransparencyLayer' except that the content of the
  transparency layer will be bounded by `rect' (specified in user space). */

CG_EXTERN void CGContextBeginTransparencyLayerWithRect(
    CGContextRef __nullable c, CGRect rect, CFDictionaryRef __nullable auxInfo)
    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* End a tranparency layer. */

CG_EXTERN void CGContextEndTransparencyLayer(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_3, __IPHONE_2_0);

/** User space to device space tranformations. **/

/* Return the affine transform mapping the user space (abstract coordinates)
   of `context' to device space (pixels). */

CG_EXTERN CGAffineTransform
    CGContextGetUserSpaceToDeviceSpaceTransform(CGContextRef __nullable c)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Transform `point' from the user space of `context' to device space. */

CG_EXTERN CGPoint CGContextConvertPointToDeviceSpace(CGContextRef __nullable c,
    CGPoint point)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Transform `point' from device space to the user space of `context'. */

CG_EXTERN CGPoint CGContextConvertPointToUserSpace(CGContextRef __nullable c,
    CGPoint point)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Transform `size' from the user space of `context' to device space. */

CG_EXTERN CGSize CGContextConvertSizeToDeviceSpace(CGContextRef __nullable c,
    CGSize size)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Transform `size' from device space to the user space of `context'. */

CG_EXTERN CGSize CGContextConvertSizeToUserSpace(CGContextRef __nullable c,
    CGSize size)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Transform `rect' from the user space of `context' to device space. Since
   affine transforms do not preserve rectangles in general, this function
   returns the smallest rectangle which contains the transformed corner
   points of `rect'. */

CG_EXTERN CGRect CGContextConvertRectToDeviceSpace(CGContextRef __nullable c,
    CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Transform `rect' from device space to the user space of `context'. Since
   affine transforms do not preserve rectangles in general, this function
   returns the smallest rectangle which contains the transformed corner
   points of `rect'. */

CG_EXTERN CGRect CGContextConvertRectToUserSpace(CGContextRef __nullable c,
    CGRect rect)
    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/** Deprecated functions. **/

/* DEPRECATED; use the CoreText API instead. */

CG_EXTERN void CGContextSelectFont(CGContextRef __nullable c,
    const char * __nullable name, CGFloat size, CGTextEncoding textEncoding)
    CG_AVAILABLE_BUT_DEPRECATED(__MAC_10_0, __MAC_10_9,
                                __IPHONE_2_0, __IPHONE_7_0);

/* DEPRECATED; use the CoreText API instead. */

CG_EXTERN void CGContextShowText(CGContextRef __nullable c,
    const char * __nullable string, size_t length)
    CG_AVAILABLE_BUT_DEPRECATED(__MAC_10_0, __MAC_10_9,
                                __IPHONE_2_0, __IPHONE_7_0);

/* DEPRECATED; use the CoreText API instead. */

CG_EXTERN void CGContextShowTextAtPoint(CGContextRef __nullable c,
    CGFloat x, CGFloat y, const char * __nullable string, size_t length)
    CG_AVAILABLE_BUT_DEPRECATED(__MAC_10_0, __MAC_10_9,
                                __IPHONE_2_0, __IPHONE_7_0);

/* DEPRECATED; use the CoreText API instead. */

CG_EXTERN void CGContextShowGlyphs(CGContextRef __nullable c,
    const CGGlyph * __nullable g, size_t count)
    CG_AVAILABLE_BUT_DEPRECATED(__MAC_10_0, __MAC_10_9,
                                __IPHONE_2_0, __IPHONE_7_0);

/* DEPRECATED; use the CoreText API instead. */

CG_EXTERN void CGContextShowGlyphsAtPoint(CGContextRef __nullable c, CGFloat x,
    CGFloat y, const CGGlyph * __nullable glyphs, size_t count)
    CG_AVAILABLE_BUT_DEPRECATED(__MAC_10_0, __MAC_10_9,
                                __IPHONE_2_0, __IPHONE_7_0);

/* DEPRECATED; use the CoreText API instead. */

CG_EXTERN void CGContextShowGlyphsWithAdvances(CGContextRef __nullable c,
    const CGGlyph * __nullable glyphs, const CGSize * __nullable advances,
    size_t count)
    CG_AVAILABLE_BUT_DEPRECATED(__MAC_10_3, __MAC_10_9,
                                __IPHONE_2_0, __IPHONE_7_0);

/* DEPRECATED; use the CGPDFPage API instead. */

CG_EXTERN void CGContextDrawPDFDocument(CGContextRef __nullable c, CGRect rect,
    CGPDFDocumentRef __nullable document, int page)
    CG_AVAILABLE_BUT_DEPRECATED(__MAC_10_0, __MAC_10_5,
                                __IPHONE_NA, __IPHONE_NA);

CF_ASSUME_NONNULL_END

CF_IMPLICIT_BRIDGING_DISABLED

#endif /* CGCONTEXT_H_ */

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