msdfgen/core/rasterization.cpp

116 lines
3.9 KiB
C++

#include "rasterization.h"
#include <vector>
#include "arithmetics.hpp"
#include "Scanline.h"
namespace msdfgen {
static bool interpretFillRule(int intersections, FillRule fillRule) {
switch (fillRule) {
case FILL_NONZERO:
return intersections != 0;
case FILL_ODD:
return intersections&1;
case FILL_POSITIVE:
return intersections > 0;
case FILL_NEGATIVE:
return intersections < 0;
}
return false;
}
void rasterize(const BitmapRef<float, 1> &output, const Shape &shape, const Vector2 &scale, const Vector2 &translate, FillRule fillRule) {
Point2 p;
Scanline scanline;
for (int y = 0; y < output.height; ++y) {
int row = shape.inverseYAxis ? output.height-y-1 : y;
p.y = (y+.5)/scale.y-translate.y;
shape.scanline(scanline, p.y);
for (int x = 0; x < output.width; ++x) {
p.x = (x+.5)/scale.x-translate.x;
int intersections = scanline.sumIntersections(p.x);
bool fill = interpretFillRule(intersections, fillRule);
*output(x, row) = (float) fill;
}
}
}
void distanceSignCorrection(const BitmapRef<float, 1> &sdf, const Shape &shape, const Vector2 &scale, const Vector2 &translate, FillRule fillRule) {
Point2 p;
Scanline scanline;
for (int y = 0; y < sdf.height; ++y) {
int row = shape.inverseYAxis ? sdf.height-y-1 : y;
p.y = (y+.5)/scale.y-translate.y;
shape.scanline(scanline, p.y);
for (int x = 0; x < sdf.width; ++x) {
p.x = (x+.5)/scale.x-translate.x;
int intersections = scanline.sumIntersections(p.x);
bool fill = interpretFillRule(intersections, fillRule);
float &sd = *sdf(x, row);
if ((sd > .5f) != fill)
sd = 1.f-sd;
}
}
}
void distanceSignCorrection(const BitmapRef<float, 3> &sdf, const Shape &shape, const Vector2 &scale, const Vector2 &translate, FillRule fillRule) {
int w = sdf.width, h = sdf.height;
if (!(w*h))
return;
Point2 p;
Scanline scanline;
bool ambiguous = false;
std::vector<char> matchMap;
matchMap.resize(w*h);
char *match = &matchMap[0];
for (int y = 0; y < h; ++y) {
int row = shape.inverseYAxis ? h-y-1 : y;
p.y = (y+.5)/scale.y-translate.y;
shape.scanline(scanline, p.y);
for (int x = 0; x < w; ++x) {
p.x = (x+.5)/scale.x-translate.x;
int intersections = scanline.sumIntersections(p.x);
bool fill = interpretFillRule(intersections, fillRule);
float *msd = sdf(x, row);
float sd = median(msd[0], msd[1], msd[2]);
if (sd == .5f)
ambiguous = true;
else if ((sd > .5f) != fill) {
msd[0] = 1.f-msd[0];
msd[1] = 1.f-msd[1];
msd[2] = 1.f-msd[2];
*match = -1;
} else
*match = 1;
++match;
}
}
// This step is necessary to avoid artifacts when whole shape is inverted
if (ambiguous) {
match = &matchMap[0];
for (int y = 0; y < h; ++y) {
int row = shape.inverseYAxis ? h-y-1 : y;
for (int x = 0; x < w; ++x) {
if (!*match) {
int neighborMatch = 0;
if (x > 0) neighborMatch += *(match-1);
if (x < w-1) neighborMatch += *(match+1);
if (y > 0) neighborMatch += *(match-w);
if (y < h-1) neighborMatch += *(match+w);
if (neighborMatch < 0) {
float *msd = sdf(x, row);
msd[0] = 1.f-msd[0];
msd[1] = 1.f-msd[1];
msd[2] = 1.f-msd[2];
}
}
++match;
}
}
}
}
}