Mirrors/MicroView-Arduino-Library
2
0
Fork 0
mirror of https://github.com/geekammo/MicroView-Arduino-Library.git synced 2026-03-02 16:24:07 +01:00
Code Issues Packages Projects Releases Wiki Activity

Fix clipping issue for circleFill when top is offscreen.

Browse Source 
Replaced circleFill algorithm with a scanning algorithm. Also fixes
problem with XOR draw mode for filled circles.
This commit is contained in:
Emil Ong
2014-08-24 14:22:30 -07:00
parent cf97ba6c23
commit 9573e7d6cc
1 changed files with 35 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
MicroView.cpp
View File

@@ -591,7 +591,6 @@ void MicroView::circle(uint8_t x0, uint8_t y0, uint8_t radius, uint8_t color, ui
pixel(x0 - y, y0 + x, color, mode);
pixel(x0 + y, y0 - x, color, mode);
pixel(x0 - y, y0 - x, color, mode);
}
}
@@ -608,38 +607,44 @@ void MicroView::circleFill(uint8_t x0, uint8_t y0, uint8_t radius) {
Draw filled circle with radius using color and mode at x,y of the screen buffer.
*/
void MicroView::circleFill(uint8_t x0, uint8_t y0, uint8_t radius, uint8_t color, uint8_t mode) {
// TODO - - find a way to check for no overlapping of pixels so that XOR draw mode will work perfectly
int8_t f = 1 - radius;
int8_t ddF_x = 1;
int8_t ddF_y = -2 * radius;
int8_t x = 0;
int8_t y = radius;
// Temporary disable fill circle for XOR mode.
if (mode==XOR) return;
for (uint8_t i=y0-radius; i<=y0+radius; i++) {
pixel(x0, i, color, mode);
// Don't bother trying to draw something totally offscreen
if (x0 - radius >= LCDWIDTH || y0 - radius >= LCDHEIGHT) {
return;
}
while (x<y) {
if (f >= 0) {
y--;
ddF_y += 2;
f += ddF_y;
}
x++;
ddF_x += 2;
f += ddF_x;
// High-level algorithm overview:
// Scan horizontally from left to right, then top to bottom, checking if each pixel
// is within the circle. We use uint16_t's because even the small screen squares beyond 8 bits.
uint16_t radiusSq = radius * radius;
for (uint8_t i=y0-y; i<=y0+y; i++) {
pixel(x0+x, i, color, mode);
pixel(x0-x, i, color, mode);
}
for (uint8_t i=y0-x; i<=y0+x; i++) {
pixel(x0+y, i, color, mode);
pixel(x0-y, i, color, mode);
}
// Optimization: define the start and end onscreen
uint16_t xStart = max(0, x0-radius);
uint16_t xEnd = min(LCDWIDTH-1, x0+radius);
uint16_t yStart = max(0, y0-radius);
uint16_t yEnd = min(LCDHEIGHT-1, y0+radius);
// scan horizontally...
for (uint16_t x = xStart; x <= xEnd; ++x) {
// Optimization: Record where if we have intersected the circle on this vertical
// scan. Once we have intersected, then don't intersect anymore, don't bother
// drawing; we've exited the circle.
bool intersected = false;
// Optimization: relative x squared only changes with the outer loop/the horizontal scan.
int16_t rx2 = (x-x0) * (x-x0);
// Scan vertically...
for (uint16_t y = yStart; y <= yEnd; ++y) {
int16_t ry2 = (y-y0) * (y-y0);
if (rx2 + ry2 <= radiusSq) {
pixel(x, y, color, mode);
intersected = true;
}
else if (intersected) {
// We've left the circle. Move on to the next horizontal scan line.
break;
}
}
}
}