SkDistanceFieldGen.h File Reference

#include "include/core/SkTypes.h"
#include <cstddef>

Go to the source code of this file.

Macros
#define	SK_DistanceFieldMagnitude   4
#define	SK_DistanceFieldPad   4
#define	SK_DistanceFieldInset   2
#define	SK_DistanceFieldMultiplier   "7.96875"
#define	SK_DistanceFieldThreshold   "0.50196078431"

Functions
bool	SkGenerateDistanceFieldFromA8Image (unsigned char *distanceField, const unsigned char *image, int w, int h, size_t rowBytes)
bool	SkGenerateDistanceFieldFromLCD16Mask (unsigned char *distanceField, const unsigned char *image, int w, int h, size_t rowBytes)
bool	SkGenerateDistanceFieldFromBWImage (unsigned char *distanceField, const unsigned char *image, int w, int h, size_t rowBytes)
size_t	SkComputeDistanceFieldSize (int w, int h)

Macro Definition Documentation

SK_DistanceFieldInset

#define SK_DistanceFieldInset   2

Definition at line 23 of file SkDistanceFieldGen.h.

SK_DistanceFieldMagnitude

#define SK_DistanceFieldMagnitude   4

Definition at line 18 of file SkDistanceFieldGen.h.

SK_DistanceFieldMultiplier

#define SK_DistanceFieldMultiplier   "7.96875"

Definition at line 29 of file SkDistanceFieldGen.h.

SK_DistanceFieldPad

#define SK_DistanceFieldPad   4

Definition at line 21 of file SkDistanceFieldGen.h.

SK_DistanceFieldThreshold

#define SK_DistanceFieldThreshold   "0.50196078431"

Definition at line 30 of file SkDistanceFieldGen.h.

Function Documentation

SkComputeDistanceFieldSize()

size_t SkComputeDistanceFieldSize ( int  w, int  h  )

inline

Given width and height of original image, return size (in bytes) of distance field

Parameters

w	Width of the original image.
h	Height of the original image.

Definition at line 75 of file SkDistanceFieldGen.h.

                                                       {
    return (w + 2*SK_DistanceFieldPad) * (h + 2*SK_DistanceFieldPad) * sizeof(unsigned char);
}

SkGenerateDistanceFieldFromA8Image()

bool SkGenerateDistanceFieldFromA8Image	(	unsigned char *	distanceField,
		const unsigned char *	image,
		int	w,
		int	h,
		size_t	rowBytes
	)

Given 8-bit mask data, generate the associated distance field

Parameters

distanceField	The distance field to be generated. Should already be allocated by the client with the padding above.
image	8-bit mask we're using to generate the distance field.
w	Width of the original image.
h	Height of the original image.
rowBytes	Size of each row in the image, in bytes

Definition at line 479 of file SkDistanceFieldGen.cpp.

                                                                                {
    SkASSERT(distanceField);
    SkASSERT(image);
 
    // create temp data
    SkAutoSMalloc<1024> copyStorage((width+2)*(height+2)*sizeof(char));
    unsigned char* copyPtr = (unsigned char*) copyStorage.get();
 
    // we copy our source image into a padded copy to ensure we catch edge transitions
    // around the outside
    const unsigned char* currSrcScanLine = image;
    sk_bzero(copyPtr, (width+2)*sizeof(char));
    unsigned char* currDestPtr = copyPtr + width + 2;
    for (int i = 0; i < height; ++i) {
        *currDestPtr++ = 0;
        memcpy(currDestPtr, currSrcScanLine, width);
        currSrcScanLine += rowBytes;
        currDestPtr += width;
        *currDestPtr++ = 0;
    }
    sk_bzero(currDestPtr, (width+2)*sizeof(char));
 
    return generate_distance_field_from_image(distanceField, copyPtr, width, height);
}

SkGenerateDistanceFieldFromBWImage()

bool SkGenerateDistanceFieldFromBWImage	(	unsigned char *	distanceField,
		const unsigned char *	image,
		int	w,
		int	h,
		size_t	rowBytes
	)

Given 1-bit mask data, generate the associated distance field

Parameters

distanceField	The distance field to be generated. Should already be allocated by the client with the padding above.
image	1-bit mask we're using to generate the distance field.
w	Width of the original image.
h	Height of the original image.
rowBytes	Size of each row in the image, in bytes

Definition at line 537 of file SkDistanceFieldGen.cpp.

                                                                                {
    SkASSERT(distanceField);
    SkASSERT(image);
 
    // create temp data
    SkAutoSMalloc<1024> copyStorage((width+2)*(height+2)*sizeof(char));
    unsigned char* copyPtr = (unsigned char*) copyStorage.get();
 
    // we copy our source image into a padded copy to ensure we catch edge transitions
    // around the outside
    const unsigned char* currSrcScanLine = image;
    sk_bzero(copyPtr, (width+2)*sizeof(char));
    unsigned char* currDestPtr = copyPtr + width + 2;
    for (int i = 0; i < height; ++i) {
        *currDestPtr++ = 0;
 
        int rowWritesLeft = width;
        const unsigned char *maskPtr = currSrcScanLine;
        while (rowWritesLeft > 0) {
            unsigned mask = *maskPtr++;
            for (int j = 7; j >= 0 && rowWritesLeft; --j, --rowWritesLeft) {
                *currDestPtr++ = (mask & (1 << j)) ? 0xff : 0;
            }
        }
        currSrcScanLine += rowBytes;
 
        *currDestPtr++ = 0;
    }
    sk_bzero(currDestPtr, (width+2)*sizeof(char));
 
    return generate_distance_field_from_image(distanceField, copyPtr, width, height);
}

SkGenerateDistanceFieldFromLCD16Mask()

bool SkGenerateDistanceFieldFromLCD16Mask	(	unsigned char *	distanceField,
		const unsigned char *	image,
		int	w,
		int	h,
		size_t	rowBytes
	)

Given LCD16 mask data (not a 16-bit image), generate the associated distance field

Parameters

distanceField	The distance field to be generated. Should already be allocated by the client with the padding above.
image	16-bit LCD data we're using to generate the distance field.
w	Width of the original image.
h	Height of the original image.
rowBytes	Size of each row in the image, in bytes

Definition at line 507 of file SkDistanceFieldGen.cpp.

                                                                          {
    SkASSERT(distanceField);
    SkASSERT(image);
 
    // create temp data
    SkAutoSMalloc<1024> copyStorage((w+2)*(h+2)*sizeof(char));
    unsigned char* copyPtr = (unsigned char*) copyStorage.get();
 
    // we copy our source image into a padded copy to ensure we catch edge transitions
    // around the outside
    const uint16_t* start = reinterpret_cast<const uint16_t*>(image);
    auto currSrcScanline = SkMask::AlphaIter<SkMask::kLCD16_Format>(start);
    auto endSrcScanline = SkMask::AlphaIter<SkMask::kLCD16_Format>(start + w);
    sk_bzero(copyPtr, (w+2)*sizeof(char));
    unsigned char* currDestPtr = copyPtr + w + 2;
    for (int i = 0; i < h; ++i, currSrcScanline >>= rowBytes, endSrcScanline >>= rowBytes) {
        *currDestPtr++ = 0;
        for (auto src = currSrcScanline; src < endSrcScanline; ++src) {
            *currDestPtr++ = *src;
        }
        *currDestPtr++ = 0;
    }
    sk_bzero(currDestPtr, (w+2)*sizeof(char));
 
    return generate_distance_field_from_image(distanceField, copyPtr, w, h);
}