|
|
- // Copyright 2021 Paul Cotter (@gr1mr3aver)
- // Copyright 2021 Nick Brassel (@tzarc)
- // SPDX-License-Identifier: GPL-2.0-or-later
-
- #include "qp_internal.h"
- #include "qp_comms.h"
- #include "qp_draw.h"
-
- // Utilize 4-way symmetry to draw an ellipse
- static bool qp_ellipse_helper_impl(painter_device_t device, uint16_t centerx, uint16_t centery, uint16_t offsetx, uint16_t offsety, bool filled) {
- /*
- Ellipses have the property of 4-way symmetry, so four pixels can be drawn
- for each computed [offsetx,offsety] given the center coordinates
- represented by [centerx,centery].
-
- For filled ellipses, we can draw horizontal lines between each pair of
- pixels with the same final value of y.
-
- When offsetx == 0 only two pixels can be drawn for filled or unfilled ellipses
- */
-
- int16_t xpx = ((int16_t)centerx) + ((int16_t)offsetx);
- int16_t xmx = ((int16_t)centerx) - ((int16_t)offsetx);
- int16_t ypy = ((int16_t)centery) + ((int16_t)offsety);
- int16_t ymy = ((int16_t)centery) - ((int16_t)offsety);
-
- if (offsetx == 0) {
- if (!qp_internal_setpixel_impl(device, xpx, ypy)) {
- return false;
- }
- if (!qp_internal_setpixel_impl(device, xpx, ymy)) {
- return false;
- }
- } else if (filled) {
- if (!qp_internal_fillrect_helper_impl(device, xpx, ypy, xmx, ypy)) {
- return false;
- }
- if (offsety > 0 && !qp_internal_fillrect_helper_impl(device, xpx, ymy, xmx, ymy)) {
- return false;
- }
- } else {
- if (!qp_internal_setpixel_impl(device, xpx, ypy)) {
- return false;
- }
- if (!qp_internal_setpixel_impl(device, xpx, ymy)) {
- return false;
- }
- if (!qp_internal_setpixel_impl(device, xmx, ypy)) {
- return false;
- }
- if (!qp_internal_setpixel_impl(device, xmx, ymy)) {
- return false;
- }
- }
-
- return true;
- }
-
- ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
- // Quantum Painter External API: qp_ellipse
-
- bool qp_ellipse(painter_device_t device, uint16_t x, uint16_t y, uint16_t sizex, uint16_t sizey, uint8_t hue, uint8_t sat, uint8_t val, bool filled) {
- qp_dprintf("qp_ellipse: entry\n");
- struct painter_driver_t *driver = (struct painter_driver_t *)device;
- if (!driver->validate_ok) {
- qp_dprintf("qp_ellipse: fail (validation_ok == false)\n");
- return false;
- }
-
- int16_t aa = ((int16_t)sizex) * ((int16_t)sizex);
- int16_t bb = ((int16_t)sizey) * ((int16_t)sizey);
- int16_t fa = 4 * ((int16_t)aa);
- int16_t fb = 4 * ((int16_t)bb);
-
- int16_t dx = 0;
- int16_t dy = ((int16_t)sizey);
-
- qp_internal_fill_pixdata(device, QP_MAX(sizex, sizey), hue, sat, val);
-
- if (!qp_comms_start(device)) {
- qp_dprintf("qp_ellipse: fail (could not start comms)\n");
- return false;
- }
-
- bool ret = true;
- for (int16_t delta = (2 * bb) + (aa * (1 - (2 * sizey))); bb * dx <= aa * dy; dx++) {
- if (!qp_ellipse_helper_impl(device, x, y, dx, dy, filled)) {
- ret = false;
- break;
- }
- if (delta >= 0) {
- delta += fa * (1 - dy);
- dy--;
- }
- delta += bb * (4 * dx + 6);
- }
-
- dx = sizex;
- dy = 0;
-
- for (int16_t delta = (2 * aa) + (bb * (1 - (2 * sizex))); aa * dy <= bb * dx; dy++) {
- if (!qp_ellipse_helper_impl(device, x, y, dx, dy, filled)) {
- ret = false;
- break;
- }
- if (delta >= 0) {
- delta += fb * (1 - dx);
- dx--;
- }
- delta += aa * (4 * dy + 6);
- }
-
- qp_dprintf("qp_ellipse: %s\n", ret ? "ok" : "fail");
- qp_comms_stop(device);
- return ret;
- }
|