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primitives.c
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/
primitives.c
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#include <stdlib.h> /* abs */
#include "primitives.h"
void draw_hline(FBDev *dev, int x1, int x2, int y, uint32_t pixel) {
int x;
if (x1 < x2) {
for (x = x1; x < x2; x++) {
fb_draw(dev, x, y, pixel);
}
} else {
for (x = x2; x < x1; x++) {
fb_draw(dev, x, y, pixel);
}
}
}
void draw_vline(FBDev *dev, int x, int y1, int y2, uint32_t pixel) {
int y;
if (y1 < y2) {
for (y = y1; y < y2; y++) {
fb_draw(dev, x, y, pixel);
}
} else {
for (y = y2; y < y1; y++) {
fb_draw(dev, x, y, pixel);
}
}
}
void draw_line(FBDev *dev, int x1, int y1, int x2, int y2, uint32_t pixel) {
int i, dx, dy, sdx, sdy, dxabs, dyabs, x, y, px, py;
// Handle simple cases first
if (x1 == x2) {
draw_vline(dev, x1, y1, y2, pixel);
} else if (y1 == y2) {
draw_hline(dev, x1, x2, y1, pixel);
}
dx = x2 - x1; // Delta x
dy = y2 - y1; // Delta y
dxabs = abs(dx); // Absolute delta
dyabs = abs(dy); // Absolute delta
sdx = (dx > 0) ? 1 : -1; // signum function
sdy = (dy > 0) ? 1 : -1; // signum function
x = dyabs >> 1;
y = dxabs >> 1;
px = x1;
py = y1;
if (dxabs >= dyabs) {
// Draw along x
for (i = 0; i < dxabs; i++) {
y += dyabs;
if (y >= dxabs) {
y -= dxabs;
py += sdy;
}
px += sdx;
fb_draw(dev, px, py, pixel);
}
} else {
// Draw along y
for (i = 0; i < dyabs; i++) {
x += dxabs;
if (x >= dyabs) {
x -= dyabs;
px += sdx;
}
py += sdy;
fb_draw(dev, px, py, pixel);
}
}
}
void draw_circle(FBDev *dev, int cx, int cy, int radius, uint32_t pixel) {
int error = -radius;
int x = radius;
int y = 0;
while (x >= y) {
fb_draw(dev, cx + x, cy + y, pixel);
fb_draw(dev, cx - x, cy + y, pixel);
fb_draw(dev, cx + x, cy - y, pixel);
fb_draw(dev, cx - x, cy - y, pixel);
fb_draw(dev, cx + y, cy + x, pixel);
fb_draw(dev, cx - y, cy + x, pixel);
fb_draw(dev, cx + y, cy - x, pixel);
fb_draw(dev, cx - y, cy - x, pixel);
error += y;
y++;
error += y;
if (error >= 0) {
error += -x;
x--;
error += -x;
}
}
}
void draw_filled_circle(FBDev *dev, int cx, int cy, int radius, uint32_t pixel, uint32_t fill) {
int error = -radius;
int x = radius;
int y = 0;
while (x >= y) {
draw_hline(dev, cx + x, cx - x, cy + y, fill);
draw_hline(dev, cx + x, cx - x, cy - y, fill);
draw_hline(dev, cx + y, cx - y, cy + x, fill);
draw_hline(dev, cx + y, cx - y, cy - x, fill);
fb_draw(dev, cx + x, cy + y, pixel);
fb_draw(dev, cx - x, cy + y, pixel);
fb_draw(dev, cx + x, cy - y, pixel);
fb_draw(dev, cx - x, cy - y, pixel);
fb_draw(dev, cx + y, cy + x, pixel);
fb_draw(dev, cx - y, cy + x, pixel);
fb_draw(dev, cx + y, cy - x, pixel);
fb_draw(dev, cx - y, cy - x, pixel);
error += y;
y++;
error += y;
if (error >= 0) {
error += -x;
x--;
error += -x;
}
}
}
void draw_rect(FBDev *dev, int x, int y, int w, int h, uint32_t pixel) {
draw_hline(dev, x, x+w, y, pixel);
draw_hline(dev, x, x+w, y+h, pixel);
draw_vline(dev, x, y, y+h, pixel);
draw_vline(dev, x+w, y, y+h, pixel);
}
void fill_rect(FBDev *dev, int x, int y, int w, int h, uint32_t pixel, uint32_t fill) {
int i;
for (i = y; i < y+h; i++) {
draw_hline(dev, x, x+w, i, fill);
}
draw_rect(dev, x, y, w, h, pixel);
}
void draw_tri(FBDev *dev, int x1, int y1, int x2, int y2, int x3, int y3, uint32_t pixel) {
draw_line(dev, x1, y1, x2, y2, pixel);
draw_line(dev, x2, y2, x3, y3, pixel);
draw_line(dev, x3, y3, x1, y1, pixel);
}
void draw_polygon(FBDev *dev, int *vx, int *vy, int n, uint32_t pixel) {
int i;
for (i = 0; i < n; i++) {
draw_line(dev, vx[i], vx[(i+1)%n], vy[i], vy[(i+1)%n], pixel);
}
}