111 lines
3.9 KiB
C
111 lines
3.9 KiB
C
/* source/draw/sgl_draw_ring.c
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*
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* MIT License
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*
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* Copyright(c) 2023-present All contributors of SGL
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* Document reference link: https://sgl-docs.readthedocs.io
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include <sgl_core.h>
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#include <sgl_draw.h>
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#include <sgl_math.h>
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/**
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* @brief draw a ring on surface with alpha
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* @param surf: pointer of surface
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* @param area: pointer of area
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* @param cx: ring center x
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* @param cy: ring center y
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* @param radius_in: ring inner radius
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* @param radius_out: ring outer radius
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* @param color: ring color
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* @param alpha: ring alpha
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* @return none
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*/
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void sgl_draw_fill_ring(sgl_surf_t *surf, sgl_area_t *area, int16_t cx, int16_t cy, int16_t radius_in, int16_t radius_out, sgl_color_t color, uint8_t alpha)
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{
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int y2 = 0, real_r2 = 0, edge_alpha = 0;
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int in_r2 = sgl_pow2(radius_in);
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int out_r2 = sgl_pow2(radius_out);
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int in_r2_max = sgl_pow2(radius_in - 1);
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int out_r2_max = sgl_pow2(radius_out + 1);
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sgl_color_t *buf = NULL, *blend = NULL;
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sgl_area_t clip;
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if (unlikely(alpha == SGL_ALPHA_MIN)) {
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return;
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}
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if (!sgl_surf_clip(surf, area, &clip)) {
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return;
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}
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buf = sgl_surf_get_buf(surf, clip.x1 - surf->x1, clip.y1 - surf->y1);
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for (int y = clip.y1; y <= clip.y2; y++) {
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blend = buf;
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y2 = sgl_pow2(y - cy);
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for (int x = clip.x1; x <= clip.x2; x++, blend++) {
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real_r2 = sgl_pow2(x - cx) + y2;
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if (real_r2 >= out_r2_max) {
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if (x > cx) break;
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continue;
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}
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if (real_r2 < in_r2_max) {
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if (x < cx) {
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blend += ((cx - x) * 2);
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x = cx*2 - x;
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}
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continue;
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}
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if (alpha == SGL_ALPHA_MAX) {
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if (real_r2 < in_r2 ) {
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*blend = sgl_color_mixer(color, *blend, sgl_sqrt_error(real_r2));
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}
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else if (real_r2 > out_r2) {
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*blend = sgl_color_mixer(color, *blend, SGL_ALPHA_MAX - sgl_sqrt_error(real_r2));
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}
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else {
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*blend = color;
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}
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}
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else {
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if (real_r2 < in_r2 ) {
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edge_alpha = sgl_sqrt_error(real_r2);
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sgl_color_t color_mix = sgl_color_mixer(color, *blend, edge_alpha);
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*blend = sgl_color_mixer(color_mix, *blend, alpha);
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}
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else if (real_r2 > out_r2) {
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edge_alpha = SGL_ALPHA_MAX - sgl_sqrt_error(real_r2);
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sgl_color_t color_mix = sgl_color_mixer(color, *blend, edge_alpha);
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*blend = sgl_color_mixer(color_mix, *blend, alpha);
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}
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else {
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*blend = sgl_color_mixer(color, *blend, alpha);
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}
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}
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}
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buf += surf->w;
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}
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}
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