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; +} | 
