/* * ASCII/ANSI art decoder * Copyright (c) 2010 Peter Ross <pross@xvid.org> * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * ASCII/ANSI art decoder */ #include "libavutil/common.h" #include "libavutil/frame.h" #include "libavutil/lfg.h" #include "avcodec.h" #include "cga_data.h" #include "internal.h" #define ATTR_BOLD 0x01 /**< Bold/Bright-foreground (mode 1) */ #define ATTR_FAINT 0x02 /**< Faint (mode 2) */ #define ATTR_UNDERLINE 0x08 /**< Underline (mode 4) */ #define ATTR_BLINK 0x10 /**< Blink/Bright-background (mode 5) */ #define ATTR_REVERSE 0x40 /**< Reverse (mode 7) */ #define ATTR_CONCEALED 0x80 /**< Concealed (mode 8) */ #define DEFAULT_FG_COLOR 7 /**< CGA color index */ #define DEFAULT_BG_COLOR 0 #define DEFAULT_SCREEN_MODE 3 /**< 80x25 */ #define FONT_WIDTH 8 /**< Font width */ /** map ansi color index to cga palette index */ static const uint8_t ansi_to_cga[16] = { 0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15 }; typedef struct { AVFrame *frame; int x; /**< x cursor position (pixels) */ int y; /**< y cursor position (pixels) */ int sx; /**< saved x cursor position (pixels) */ int sy; /**< saved y cursor position (pixels) */ const uint8_t* font; /**< font */ int font_height; /**< font height */ int attributes; /**< attribute flags */ int fg; /**< foreground color */ int bg; /**< background color */ /* ansi parser state machine */ enum { STATE_NORMAL = 0, STATE_ESCAPE, STATE_CODE, STATE_MUSIC_PREAMBLE } state; #define MAX_NB_ARGS 4 int args[MAX_NB_ARGS]; int nb_args; /**< number of arguments (may exceed MAX_NB_ARGS) */ } AnsiContext; static av_cold int decode_init(AVCodecContext *avctx) { AnsiContext *s = avctx->priv_data; avctx->pix_fmt = AV_PIX_FMT_PAL8; s->frame = av_frame_alloc(); if (!s->frame) return AVERROR(ENOMEM); /* defaults */ s->font = ff_vga16_font; s->font_height = 16; s->fg = DEFAULT_FG_COLOR; s->bg = DEFAULT_BG_COLOR; if (!avctx->width || !avctx->height) { int ret = ff_set_dimensions(avctx, 80 << 3, 25 << 4); if (ret < 0) return ret; } return 0; } static void hscroll(AVCodecContext *avctx) { AnsiContext *s = avctx->priv_data; int i; if (s->y < avctx->height - s->font_height) { s->y += s->font_height; return; } i = 0; for (; i < avctx->height - s->font_height; i++) memcpy(s->frame->data[0] + i * s->frame->linesize[0], s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0], avctx->width); for (; i < avctx->height; i++) memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width); } static void erase_line(AVCodecContext * avctx, int xoffset, int xlength) { AnsiContext *s = avctx->priv_data; int i; for (i = 0; i < s->font_height; i++) memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset, DEFAULT_BG_COLOR, xlength); } static void erase_screen(AVCodecContext *avctx) { AnsiContext *s = avctx->priv_data; int i; for (i = 0; i < avctx->height; i++) memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width); s->x = s->y = 0; } /** * Draw character to screen */ static void draw_char(AVCodecContext *avctx, int c) { AnsiContext *s = avctx->priv_data; int fg = s->fg; int bg = s->bg; if ((s->attributes & ATTR_BOLD)) fg += 8; if ((s->attributes & ATTR_BLINK)) bg += 8; if ((s->attributes & ATTR_REVERSE)) FFSWAP(int, fg, bg); if ((s->attributes & ATTR_CONCEALED)) fg = bg; ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x, s->frame->linesize[0], s->font, s->font_height, c, fg, bg); s->x += FONT_WIDTH; if (s->x >= avctx->width) { s->x = 0; hscroll(avctx); } } /** * Execute ANSI escape code * @return 0 on success, negative on error */ static int execute_code(AVCodecContext * avctx, int c) { AnsiContext *s = avctx->priv_data; int ret, i; int width = 0; int height = 0; switch(c) { case 'A': //Cursor Up s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0); break; case 'B': //Cursor Down s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height); break; case 'C': //Cursor Right s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH); break; case 'D': //Cursor Left s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0); break; case 'H': //Cursor Position case 'f': //Horizontal and Vertical Position s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0; s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0; break; case 'h': //set creen mode case 'l': //reset screen mode if (s->nb_args < 2) s->args[0] = DEFAULT_SCREEN_MODE; switch(s->args[0]) { case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows) s->font = ff_cga_font; s->font_height = 8; width = 40<<3; height = 25<<3; break; case 2: case 3: //640x400 (25 rows) s->font = ff_vga16_font; s->font_height = 16; width = 80<<3; height = 25<<4; break; case 6: case 14: //640x200 (25 rows) s->font = ff_cga_font; s->font_height = 8; width = 80<<3; height = 25<<3; break; case 7: //set line wrapping break; case 15: case 16: //640x350 (43 rows) s->font = ff_cga_font; s->font_height = 8; width = 80<<3; height = 43<<3; break; case 17: case 18: //640x480 (60 rows) s->font = ff_cga_font; s->font_height = 8; width = 80<<3; height = 60<<4; break; default: avpriv_request_sample(avctx, "Unsupported screen mode"); } if (width != 0 && height != 0 && (width != avctx->width || height != avctx->height)) { av_frame_unref(s->frame); ret = ff_set_dimensions(avctx, width, height); if (ret < 0) return ret; ret = ff_get_buffer(avctx, s->frame, AV_GET_BUFFER_FLAG_REF); if (ret < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return ret; } s->frame->pict_type = AV_PICTURE_TYPE_I; s->frame->palette_has_changed = 1; memcpy(s->frame->data[1], ff_cga_palette, 16 * 4); erase_screen(avctx); } else if (c == 'l') { erase_screen(avctx); } break; case 'J': //Erase in Page switch (s->args[0]) { case 0: erase_line(avctx, s->x, avctx->width - s->x); if (s->y < avctx->height - s->font_height) memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0], DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]); break; case 1: erase_line(avctx, 0, s->x); if (s->y > 0) memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]); break; case 2: erase_screen(avctx); } break; case 'K': //Erase in Line switch(s->args[0]) { case 0: erase_line(avctx, s->x, avctx->width - s->x); break; case 1: erase_line(avctx, 0, s->x); break; case 2: erase_line(avctx, 0, avctx->width); } break; case 'm': //Select Graphics Rendition if (s->nb_args == 0) { s->nb_args = 1; s->args[0] = 0; } for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) { int m = s->args[i]; if (m == 0) { s->attributes = 0; s->fg = DEFAULT_FG_COLOR; s->bg = DEFAULT_BG_COLOR; } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) { s->attributes |= 1 << (m - 1); } else if (m >= 30 && m <= 38) { s->fg = ansi_to_cga[m - 30]; } else if (m == 39) { s->fg = ansi_to_cga[DEFAULT_FG_COLOR]; } else if (m >= 40 && m <= 47) { s->bg = ansi_to_cga[m - 40]; } else if (m == 49) { s->fg = ansi_to_cga[DEFAULT_BG_COLOR]; } else { avpriv_request_sample(avctx, "Unsupported rendition parameter"); } } break; case 'n': //Device Status Report case 'R': //report current line and column /* ignore */ break; case 's': //Save Cursor Position s->sx = s->x; s->sy = s->y; break; case 'u': //Restore Cursor Position s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH); s->y = av_clip(s->sy, 0, avctx->height - s->font_height); break; default: avpriv_request_sample(avctx, "Unknown escape code"); break; } return 0; } static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { AnsiContext *s = avctx->priv_data; uint8_t *buf = avpkt->data; int buf_size = avpkt->size; const uint8_t *buf_end = buf+buf_size; int ret, i, count; ret = ff_reget_buffer(avctx, s->frame); if (ret < 0){ av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return ret; } if (!avctx->frame_number) { memset(s->frame->data[0], 0, avctx->height * FFABS(s->frame->linesize[0])); memset(s->frame->data[1], 0, AVPALETTE_SIZE); } s->frame->pict_type = AV_PICTURE_TYPE_I; s->frame->palette_has_changed = 1; memcpy(s->frame->data[1], ff_cga_palette, 16 * 4); while(buf < buf_end) { switch(s->state) { case STATE_NORMAL: switch (buf[0]) { case 0x00: //NUL case 0x07: //BEL case 0x1A: //SUB /* ignore */ break; case 0x08: //BS s->x = FFMAX(s->x - 1, 0); break; case 0x09: //HT i = s->x / FONT_WIDTH; count = ((i + 8) & ~7) - i; for (i = 0; i < count; i++) draw_char(avctx, ' '); break; case 0x0A: //LF hscroll(avctx); case 0x0D: //CR s->x = 0; break; case 0x0C: //FF erase_screen(avctx); break; case 0x1B: //ESC s->state = STATE_ESCAPE; break; default: draw_char(avctx, buf[0]); } break; case STATE_ESCAPE: if (buf[0] == '[') { s->state = STATE_CODE; s->nb_args = 0; s->args[0] = 0; } else { s->state = STATE_NORMAL; draw_char(avctx, 0x1B); continue; } break; case STATE_CODE: switch(buf[0]) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': if (s->nb_args < MAX_NB_ARGS) s->args[s->nb_args] = s->args[s->nb_args] * 10 + buf[0] - '0'; break; case ';': s->nb_args++; if (s->nb_args < MAX_NB_ARGS) s->args[s->nb_args] = 0; break; case 'M': s->state = STATE_MUSIC_PREAMBLE; break; case '=': case '?': /* ignore */ break; default: if (s->nb_args > MAX_NB_ARGS) av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args); if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args]) s->nb_args++; if ((ret = execute_code(avctx, buf[0])) < 0) return ret; s->state = STATE_NORMAL; } break; case STATE_MUSIC_PREAMBLE: if (buf[0] == 0x0E || buf[0] == 0x1B) s->state = STATE_NORMAL; /* ignore music data */ break; } buf++; } *got_frame = 1; if ((ret = av_frame_ref(data, s->frame)) < 0) return ret; return buf_size; } static av_cold int decode_close(AVCodecContext *avctx) { AnsiContext *s = avctx->priv_data; av_frame_free(&s->frame); return 0; } AVCodec ff_ansi_decoder = { .name = "ansi", .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_ANSI, .priv_data_size = sizeof(AnsiContext), .init = decode_init, .close = decode_close, .decode = decode_frame, .capabilities = CODEC_CAP_DR1, };