| 0,0 → 1,117 |
|---|
| /* |
| * Copyright 2012 Michael Drake <tlsa@netsurf-browser.org> |
| * |
| * This file is part of libnsfb, http://www.netsurf-browser.org/ |
| * Licenced under the MIT License, |
| * http://www.opensource.org/licenses/mit-license.php |
| */ |
| |
| /** \file |
| * Palette (implementation). |
| */ |
| |
| #include <assert.h> |
| #include <stdbool.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include "palette.h" |
| |
| |
| /** Create an empty palette object. */ |
| bool nsfb_palette_new(struct nsfb_palette_s **palette, int width) |
| { |
| *palette = malloc(sizeof(struct nsfb_palette_s)); |
| if (*palette == NULL) { |
| return false; |
| } |
| |
| (*palette)->type = NSFB_PALETTE_EMPTY; |
| (*palette)->last = 0; |
| |
| (*palette)->dither = false; |
| (*palette)->dither_ctx.data_len = width * 3; |
| (*palette)->dither_ctx.data = malloc(width * 3 * sizeof(int)); |
| if ((*palette)->dither_ctx.data == NULL) { |
| nsfb_palette_free(*palette); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /** Free a palette object. */ |
| void nsfb_palette_free(struct nsfb_palette_s *palette) |
| { |
| if (palette != NULL) { |
| if (palette->dither_ctx.data != NULL) { |
| free(palette->dither_ctx.data); |
| } |
| free(palette); |
| } |
| } |
| |
| /** Init error diffusion for a plot. */ |
| void nsfb_palette_dither_init(struct nsfb_palette_s *palette, int width) |
| { |
| palette->dither = true; |
| memset(palette->dither_ctx.data, 0, palette->dither_ctx.data_len); |
| palette->dither_ctx.width = width * 3; |
| palette->dither_ctx.current = 0; |
| } |
| |
| /** Finalise error diffusion after a plot. */ |
| void nsfb_palette_dither_fini(struct nsfb_palette_s *palette) |
| { |
| palette->dither = false; |
| } |
| |
| /** Generate libnsfb 8bpp default palette. */ |
| void nsfb_palette_generate_nsfb_8bpp(struct nsfb_palette_s *palette) |
| { |
| int rloop, gloop, bloop; |
| int loop = 0; |
| uint8_t r, g, b; |
| |
| /* Build a linear 6-8-5 levels RGB colour cube palette. |
| * This accounts for 240 colours */ |
| #define RLIM 6 |
| #define GLIM 8 |
| #define BLIM 5 |
| for (rloop = 0; rloop < RLIM; rloop++) { |
| for (gloop = 0; gloop < GLIM; gloop++) { |
| for (bloop = 0; bloop < BLIM; bloop++) { |
| r = ((rloop * 255 * 2) + RLIM - 1) / |
| (2 * (RLIM - 1)); |
| g = ((gloop * 255 * 2) + GLIM - 1) / |
| (2 * (GLIM - 1)); |
| b = ((bloop * 255 * 2) + BLIM - 1) / |
| (2 * (BLIM - 1)); |
| |
| palette->data[loop] = r | g << 8 | b << 16; |
| loop++; |
| } |
| } |
| } |
| #undef RLIM |
| #undef GLIM |
| #undef BLIM |
| |
| /* Should have 240 colours set */ |
| assert(loop == 240); |
| |
| /* Fill index 240 to index 255 with grayscales */ |
| /* Note: already have full black and full white from RGB cube */ |
| for (; loop < 256; loop++) { |
| int ngray = loop - 240 + 1; |
| r = ngray * 15; /* 17*15 = 255 */ |
| |
| g = b = r; |
| |
| palette->data[loop] = r | g << 8 | b << 16; |
| } |
| |
| /* Set palette details */ |
| palette->type = NSFB_PALETTE_NSFB_8BPP; |
| palette->last = 255; |
| } |