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Util: Add mPainterDrawCircle

This commit is contained in:
Vicki Pfau 2023-07-27 20:26:08 -07:00
parent ba49175697
commit 57ba653bc7
3 changed files with 229 additions and 8 deletions
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1
include/mgba-util/image.h
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@ -137,6 +137,7 @@ void mImageCompositeWithAlpha(struct mImage* image, const struct mImage* source,
void mPainterInit(struct mPainter*, struct mImage* backing);
void mPainterDrawRectangle(struct mPainter*, int x, int y, int width, int height);
void mPainterDrawLine(struct mPainter*, int x1, int y1, int x2, int y2);
void mPainterDrawCircle(struct mPainter*, int x, int y, int diameter);
uint32_t mColorConvert(uint32_t color, enum mColorFormat from, enum mColorFormat to);
uint32_t mImageColorConvert(uint32_t color, const struct mImage* from, enum mColorFormat to);

144
src/util/image.c
View File

@ -557,6 +557,13 @@ void mPainterInit(struct mPainter* painter, struct mImage* backing) {
painter->backing = backing;
}
static void mPainterDrawPixel(struct mPainter* painter, unsigned x, unsigned y, uint32_t color) {
if (painter->blend) {
color = mColorMixARGB8(painter->strokeColor, mImageGetPixel(painter->backing, x, y));
}
mImageSetPixel(painter->backing, x, y, color);
}
static void mPainterFillRectangle(struct mPainter* painter, int x, int y, int width, int height) {
FILL_BOUNDS_INIT(x, y, width, height);
@ -651,10 +658,7 @@ void mPainterDrawLine(struct mPainter* painter, int x1, int y1, int x2, int y2)
y = y1;
for (x = x1; x != x2 + xi; x += xi) {
for (i = 0; i < painter->strokeWidth; ++i) {
if (painter->blend) {
color = mColorMixARGB8(painter->strokeColor, mImageGetPixel(painter->backing, x, y - painter->strokeWidth / 2 + i));
}
mImageSetPixel(painter->backing, x, y - painter->strokeWidth / 2 + i, color);
mPainterDrawPixel(painter, x, y - painter->strokeWidth / 2 + i, color);
}
if (residual > 0) {
y += yi;
@ -667,10 +671,7 @@ void mPainterDrawLine(struct mPainter* painter, int x1, int y1, int x2, int y2)
x = x1;
for (y = y1; y != y2 + yi; y += yi) {
for (i = 0; i < painter->strokeWidth; ++i) {
if (painter->blend) {
color = mColorMixARGB8(painter->strokeColor, mImageGetPixel(painter->backing, x - painter->strokeWidth / 2 + i, y));
}
mImageSetPixel(painter->backing, x - painter->strokeWidth / 2 + i, y, color);
mPainterDrawPixel(painter, x - painter->strokeWidth / 2 + i, y, color);
}
if (residual > 0) {
x += xi;
@ -683,6 +684,133 @@ void mPainterDrawLine(struct mPainter* painter, int x1, int y1, int x2, int y2)
// TODO: Draw endcaps for widths >2
}
static void _drawCircleOctants(struct mPainter* painter, int x, int y, int offx, int offy, int offset, uint32_t color) {
mPainterDrawPixel(painter, x + offy - offset, y + offx - offset, color);
mPainterDrawPixel(painter, x - offy, y + offx - offset, color);
mPainterDrawPixel(painter, x + offy - offset, y - offx, color);
mPainterDrawPixel(painter, x - offy, y - offx, color);
if (offx < offy) {
mPainterDrawPixel(painter, x + offx - offset, y + offy - offset, color);
mPainterDrawPixel(painter, x - offx, y + offy - offset, color);
mPainterDrawPixel(painter, x + offx - offset, y - offy, color);
mPainterDrawPixel(painter, x - offx, y - offy, color);
}
}
static void _drawCircle2x2(struct mPainter* painter, int x, int y, uint32_t color) {
mPainterDrawPixel(painter, x, y, color);
mPainterDrawPixel(painter, x - 1, y, color);
mPainterDrawPixel(painter, x, y - 1, color);
mPainterDrawPixel(painter, x - 1, y - 1, color);
}
void mPainterDrawCircle(struct mPainter* painter, int x, int y, int diameter) {
int radius = diameter / 2;
int offset = (diameter ^ 1) & 1;
int stroke = painter->strokeWidth;
int dx = 1;
int residual0 = 1 - radius;
int dy0 = -2 * radius;
int offx = 0;
int offy;
int y0 = radius;
if (stroke > radius) {
// Clamp stroke
stroke = radius;
if (!offset) {
// Draw center dot as stroke
mPainterDrawPixel(painter, x + radius, y + radius, painter->strokeColor);
}
} else if (!offset && painter->fill) {
// Draw center dot as fill
mPainterDrawPixel(painter, x + radius, y + radius, painter->fillColor);
}
int residual1 = 1 - radius + stroke;
int dy1 = -2 * (radius - stroke);
int y1 = radius - stroke;
int i;
if (!offset) {
// Draw central axes
for (i = 0; i < stroke; ++i) {
mPainterDrawPixel(painter, x + radius, y + radius * 2 - i, painter->strokeColor);
mPainterDrawPixel(painter, x + radius, y + i, painter->strokeColor);
mPainterDrawPixel(painter, x + radius * 2 - i, y + radius, painter->strokeColor);
mPainterDrawPixel(painter, x + i, y + radius, painter->strokeColor);
}
if (painter->fill) {
for (i = i; i < y1 + 1; ++i) {
mPainterDrawPixel(painter, x + radius, y + radius - i, painter->fillColor);
mPainterDrawPixel(painter, x + radius, y + radius + i, painter->fillColor);
mPainterDrawPixel(painter, x + radius - i, y + radius, painter->fillColor);
mPainterDrawPixel(painter, x + radius + i, y + radius, painter->fillColor);
}
}
}
while (offx < y0) {
if (residual0 >= 0) {
y0 -= 1;
dy0 += 2;
residual0 += dy0;
}
if (residual1 >= 0) {
y1 -= 1;
dy1 += 2;
residual1 += dy1;
}
offx += 1;
dx += 2;
residual0 += dx;
residual1 += dx;
if (stroke) {
// Fill
if (painter->fill) {
if (offx == 1 && y1 == 0 && offset) {
// Special case for diameter-2 fill
_drawCircle2x2(painter, x + radius, y + radius, painter->fillColor);
} else {
for (offy = 0; offy < y1 + 1; ++offy) {
if (offx > offy) {
continue;
}
_drawCircleOctants(painter, x + radius, y + radius, offx, offy, offset, painter->fillColor);
}
}
}
// Stroke
if (radius == 1 && offset) {
// Special case for diameter-2 stroke
_drawCircle2x2(painter, x + radius, y + radius, painter->strokeColor);
} else {
for (offy = y1 + 1; offy < y0 + 1; ++offy) {
if (offx == 1 && offy == 1 && y1 == 0 && offset) {
// Special case for diameter-2 inner fill
continue;
}
if (offx > offy) {
continue;
}
_drawCircleOctants(painter, x + radius, y + radius, offx, offy, offset, painter->strokeColor);
}
}
} else if (painter->fill) {
if (offx == 1 && y0 == 0 && offset) {
// Special case for diameter-2 fill
_drawCircle2x2(painter, x, y, painter->fillColor);
} else {
for (offy = 0; offy < y0 + 1; ++offy) {
if (offx > offy) {
continue;
}
_drawCircleOctants(painter, x + radius, y + radius, offx, offy, offset, painter->fillColor);
}
}
}
}
}
uint32_t mColorConvert(uint32_t color, enum mColorFormat from, enum mColorFormat to) {
if (from == to) {
return color;

92
src/util/test/image.c
View File

@ -1849,6 +1849,95 @@ M_TEST_DEFINE(painterDrawLineBlend) {
mImageDestroy(image);
}
M_TEST_DEFINE(painterDrawCircleArea) {
struct mImage* image;
struct mPainter painter;
int i;
for (i = 4; i < 50; ++i) {
image = mImageCreate(i, i, mCOLOR_XRGB8);
mPainterInit(&painter, image);
painter.blend = false;
painter.fill = true;
painter.strokeWidth = 0;
painter.fillColor = 0xFF0000FF;
mPainterDrawCircle(&painter, 0, 0, i);
int filled = 0;
int x, y;
for (y = 0; y < i; ++y) {
for (x = 0; x < i; ++x) {
uint32_t color = mImageGetPixel(image, x, y);
if (color == painter.fillColor) {
++filled;
}
}
}
float area = i * i;
assert_float_equal(filled / area, M_PI / 4, 0.12);
}
}
M_TEST_DEFINE(painterDrawCircleCircumference) {
struct mImage* image;
struct mPainter painter;
int i;
for (i = 25; i < 100; ++i) {
image = mImageCreate(i, i, mCOLOR_XRGB8);
mPainterInit(&painter, image);
painter.blend = false;
painter.fill = false;
painter.strokeWidth = 1;
painter.strokeColor = 0xFF0000FF;
mPainterDrawCircle(&painter, 0, 0, i);
int filled = 0;
int x, y;
for (y = 0; y < i; ++y) {
for (x = 0; x < i; ++x) {
uint32_t color = mImageGetPixel(image, x, y);
if (color == painter.strokeColor) {
++filled;
}
}
}
assert_float_equal(filled / (float) i, M_PI, M_PI * 0.11);
}
}
M_TEST_DEFINE(painterDrawCircleOffset) {
struct mImage* image;
struct mPainter painter;
int i;
for (i = 4; i < 20; ++i) {
image = mImageCreate(i * 2, i * 2, mCOLOR_XRGB8);
mPainterInit(&painter, image);
painter.blend = false;
painter.fill = true;
painter.strokeWidth = 0;
painter.fillColor = 0xFF0000FF;
mPainterDrawCircle(&painter, 0, 0, i);
mPainterDrawCircle(&painter, i, 0, i);
mPainterDrawCircle(&painter, 0, i, i);
mPainterDrawCircle(&painter, i, i, i);
int x, y;
for (y = 0; y < i; ++y) {
for (x = 0; x < i; ++x) {
uint32_t color = mImageGetPixel(image, x, y);
assert_int_equal(color, mImageGetPixel(image, x + i, y));
assert_int_equal(color, mImageGetPixel(image, x, y + i));
assert_int_equal(color, mImageGetPixel(image, x + i, y + i));
}
}
}
}
#undef COMPARE3X
#undef COMPARE3
#undef COMPARE4X
@ -1887,4 +1976,7 @@ M_TEST_SUITE_DEFINE(Image,
cmocka_unit_test(painterDrawLineOctants),
cmocka_unit_test(painterDrawLineWidth),
cmocka_unit_test(painterDrawLineBlend),
cmocka_unit_test(painterDrawCircleArea),
cmocka_unit_test(painterDrawCircleCircumference),
cmocka_unit_test(painterDrawCircleOffset),
)