168 lines
7.7 KiB
C
168 lines
7.7 KiB
C
/* *****************************************************************************
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* libg1m/picture.h -- libg1m picture formats.
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* Copyright (C) 2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
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*
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* This file is part of libg1m.
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* libg1m is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 3.0 of the License,
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* or (at your option) any later version.
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*
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* libg1m is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with libg1m; if not, see <http://www.gnu.org/licenses/>.
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* ************************************************************************** */
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#ifndef LIBG1M_PICTURE_H
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# define LIBG1M_PICTURE_H
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# include <libg1m/color.h>
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/* This file describes the picture formats CASIO has used for various purposes
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* (screenshots, pictures, screenstreaming), and that libg1m is able to
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* decode.
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*
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* The formats pictures should fit in a `g1m_pictureformat_t`.
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* They are more or less organized as 0xBBVS, where BB is the number of bits
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* each pixel occupy (in total), V is the variation for this number of bits,
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* and S is the special hex digit (e.g. reverse). */
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typedef unsigned int g1m_pictureformat_t;
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/* ************************************************************************** */
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/* Monochrome pictures with fill bits */
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/* ************************************************************************** */
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/* In this format, each bit represents a pixel (so one byte contains eight
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* pixels). If the width is not divisible by eight, then the last bits of the
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* last byte of the line are unused (fill bits), and the next line starts at
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* the beginning of the next byte ; this makes the navigation between lines
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* easier, but takes up more space.
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*
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* An off bit (0b0) represents a white pixel, and an on bit (0b1) represents
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* a black pixel. Reverse white and black in the `_r` special type. */
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# define g1m_pictureformat_1bit 0x0100
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# define g1m_pictureformat_1bit_r 0x0101
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/* To calculate the size, it's simple: just calculate the number of bytes
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* a line occupies, then multiply it by the number of lines. */
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# define g1m_picturesize_1bit(W, H) \
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((((W) / 8) + !!((W) % 8)) * (H))
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# define g1m_picturesize_1bit_r(W, H) \
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g1m_picturesize_1bit((W), (H))
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/* ************************************************************************** */
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/* Packed monochrome pictures */
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/* ************************************************************************** */
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/* Packed monochrome pictures is basically the same than the previous format,
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* except there are no fill bits: if a picture width is 6 pixels, then the
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* second line will start at the seventh bit of the first byte (where it would
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* start at the first bit of the second byte with fill bits).
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*
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* The navigation to a line is less easy as it takes at least one division. */
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# define g1m_pictureformat_1bit_packed 0x0110
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# define g1m_pictureformat_1bit_packed_r 0x0111
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/* To calculate the size, find out the number of occupied bits, divide by
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* eight to get the bytes, and make sure to keep an extra byte if there are
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* left bits. */
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# define g1m_picturesize_1bit_packed(W, H) \
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(((W) * (H) / 8) + !!((W) * (H) % 8))
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/* ************************************************************************** */
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/* Old monochrome format */
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/* ************************************************************************** */
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/* The old monochrome format used by CASIO is basically a normal monochrome
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* format (the width is usually 96 or 128, so no need for fill bits), except
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* that it starts with the last byte (where the bits are in left to right
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* order), but then it goes from right to left, and from bottom to top. */
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# define g1m_pictureformat_1bit_old 0x0120
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/* The size is the same as for normal 1-bit monochrome pictures, only the
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* byte order changes. */
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# define g1m_picturesize_1bit_old(W, H) \
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g1m_picturesize_1bit(W, H)
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/* ************************************************************************** */
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/* Dual monochrome format */
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/* ************************************************************************** */
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/* This is the format used for the Prizm's projector mode. It is composed of
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* two monochrome pictures (with sizes divisible by eight).
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* It is basically gray pictures, with white, light gray, dark gray and
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* black. */
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# define g1m_pictureformat_2bit_dual 0x0200
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/* To calculate the size, well, we just have two monochrome screens. */
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# define g1m_picturesize_2bit_dual(W, H) \
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(g1m_picturesize_1bit(W, H) * 2)
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/* ************************************************************************** */
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/* 4-bit RGB_ format */
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/* ************************************************************************** */
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/* This is a 4 bit per pixel format. There is no need for fill bits (?).
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* Each nibble (group of 4 bits) is made of the following:
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* - one bit for red (OR by 0xFF0000);
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* - one bit for green (OR by 0x00FF00);
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* - one bit for blue (OR by 0x0000FF);
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* - one alignment bit. */
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# define g1m_pictureformat_4bit 0x0400
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# define g1m_pictureformat_4bit_rgb 0x0400
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/* Calculating the size is trivial. */
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# define g1m_picturesize_4bit(W, H) \
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((W) * (H) / 2)
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# define g1m_picturesize_4bit_rgb(W, H) \
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g1m_picturesize_4bit(W, H)
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/* ************************************************************************** */
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/* 4-bit code format */
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/* ************************************************************************** */
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/* In this encoding, each nibble for a pixel represents one of the color codes
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* defined in `libg1m/color.h`. */
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# define g1m_pictureformat_4bit_code 0x0410
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/* The size is calculated the same way as previously. */
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# define g1m_picturesize_4bit_code(W, H) \
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g1m_picturesize_4bit(W, H)
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/* ************************************************************************** */
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/* Quad-monochrome VRAM formats */
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/* ************************************************************************** */
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/* This format is used by old CASIO models. It is made of four monochrome
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* pictures (no need for fill bits), where the palettes are:
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* - for the `color` variant: [orange, green, blue, white (bg)]
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* - for the `mono` variant: [(unused), (unused), black, white (bg)] */
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# define g1m_pictureformat_4bit_color 0x0420
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# define g1m_pictureformat_4bit_mono 0x0421
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/* Just multiply the size of a VRAM by four. */
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# define g1m_picturesize_4bit_color(W, H) \
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(4 * g1m_picturesize_1bit_old(W, H))
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# define g1m_picturesize_4bit_mono(W, H) \
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g1m_picturesize_4bit_color(W, H)
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/* ************************************************************************** */
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/* 16-bit R5G6B5 format */
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/* ************************************************************************** */
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/* This is the format of the Prizm's VRAM. Each pixel is two bytes long,
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* the first five bits represent the high five (clap!) bits of the red part,
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* the next six bits represent the high six bits of the green part,
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* the last five bits represent the high five (re-clap!) bits of the blue
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* part. */
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# define g1m_pictureformat_16bit 0x1000
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/* Two bytes per pixel. */
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# define g1m_picturesize_16bit(W, H) \
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((W) * (H) * 2)
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#endif /* LIBG1M_PICTURE_H */
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