diff options
Diffstat (limited to 'quantum/painter/qp_draw_circle.c')
| -rw-r--r-- | quantum/painter/qp_draw_circle.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/quantum/painter/qp_draw_circle.c b/quantum/painter/qp_draw_circle.c new file mode 100644 index 0000000000..edaae35835 --- /dev/null +++ b/quantum/painter/qp_draw_circle.c @@ -0,0 +1,172 @@ +// Copyright 2021 Paul Cotter (@gr1mr3aver) +// Copyright 2021 Nick Brassel (@tzarc) +// SPDX-License-Identifier: GPL-2.0-or-later + +#include "qp.h" +#include "qp_internal.h" +#include "qp_comms.h" +#include "qp_draw.h" + +// Utilize 8-way symmetry to draw circles +static bool qp_circle_helper_impl(painter_device_t device, uint16_t centerx, uint16_t centery, uint16_t offsetx, uint16_t offsety, bool filled) { + /* + Circles have the property of 8-way symmetry, so eight pixels can be drawn + for each computed [offsetx,offsety] given the center coordinates + represented by [centerx,centery]. + + For filled circles, we can draw horizontal lines between each pair of + pixels with the same final value of y. + + Two special cases exist and have been optimized: + 1) offsetx == offsety (the final point), makes half the coordinates + equivalent, so we can omit them (and the corresponding fill lines) + 2) offsetx == 0 (the starting point) means that some horizontal lines + would be a single pixel in length, so we write individual pixels instead. + This also makes half the symmetrical points identical to their twins, + so we only need four points or two points and one line + */ + + int16_t xpx = ((int16_t)centerx) + ((int16_t)offsetx); + int16_t xmx = ((int16_t)centerx) - ((int16_t)offsetx); + int16_t xpy = ((int16_t)centerx) + ((int16_t)offsety); + int16_t xmy = ((int16_t)centerx) - ((int16_t)offsety); + int16_t ypx = ((int16_t)centery) + ((int16_t)offsetx); + int16_t ymx = ((int16_t)centery) - ((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, centerx, ypy)) { + return false; + } + if (!qp_internal_setpixel_impl(device, centerx, ymy)) { + return false; + } + if (filled) { + if (!qp_internal_fillrect_helper_impl(device, xpy, centery, xmy, centery)) { + return false; + } + } else { + if (!qp_internal_setpixel_impl(device, xpy, centery)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xmy, centery)) { + return false; + } + } + } else if (offsetx == offsety) { + if (filled) { + if (!qp_internal_fillrect_helper_impl(device, xpy, ypy, xmy, ypy)) { + return false; + } + if (!qp_internal_fillrect_helper_impl(device, xpy, ymy, xmy, ymy)) { + return false; + } + } else { + if (!qp_internal_setpixel_impl(device, xpy, ypy)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xmy, ypy)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xpy, ymy)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xmy, ymy)) { + return false; + } + } + + } else { + if (filled) { + if (!qp_internal_fillrect_helper_impl(device, xpx, ypy, xmx, ypy)) { + return false; + } + if (!qp_internal_fillrect_helper_impl(device, xpx, ymy, xmx, ymy)) { + return false; + } + if (!qp_internal_fillrect_helper_impl(device, xpy, ypx, xmy, ypx)) { + return false; + } + if (!qp_internal_fillrect_helper_impl(device, xpy, ymx, xmy, ymx)) { + return false; + } + } else { + if (!qp_internal_setpixel_impl(device, xpx, ypy)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xmx, ypy)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xpx, ymy)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xmx, ymy)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xpy, ypx)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xmy, ypx)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xpy, ymx)) { + return false; + } + if (!qp_internal_setpixel_impl(device, xmy, ymx)) { + return false; + } + } + } + + return true; +} + +//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// Quantum Painter External API: qp_circle + +bool qp_circle(painter_device_t device, uint16_t x, uint16_t y, uint16_t radius, uint8_t hue, uint8_t sat, uint8_t val, bool filled) { + qp_dprintf("qp_circle: entry\n"); + struct painter_driver_t *driver = (struct painter_driver_t *)device; + if (!driver->validate_ok) { + qp_dprintf("qp_circle: fail (validation_ok == false)\n"); + return false; + } + + // plot the initial set of points for x, y and r + int16_t xcalc = 0; + int16_t ycalc = (int16_t)radius; + int16_t err = ((5 - (radius >> 2)) >> 2); + + qp_internal_fill_pixdata(device, (radius * 2) + 1, hue, sat, val); + + if (!qp_comms_start(device)) { + qp_dprintf("qp_circle: fail (could not start comms)\n"); + return false; + } + + bool ret = true; + if (!qp_circle_helper_impl(device, x, y, xcalc, ycalc, filled)) { + ret = false; + } + + if (ret) { + while (xcalc < ycalc) { + xcalc++; + if (err < 0) { + err += (xcalc << 1) + 1; + } else { + ycalc--; + err += ((xcalc - ycalc) << 1) + 1; + } + if (!qp_circle_helper_impl(device, x, y, xcalc, ycalc, filled)) { + ret = false; + break; + } + } + } + + qp_dprintf("qp_circle: %s\n", ret ? "ok" : "fail"); + qp_comms_stop(device); + return ret; +} |