113 lines
4.3 KiB
C
113 lines
4.3 KiB
C
/* bitmap.h: definition for a bitmap type. No packing is done by
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* default; each pixel is represented by an entire byte. Among other
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* things, this means the type can be used for both grayscale and binary
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* images.
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*
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* Copyright (C) 1992 Free Software Foundation, Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* This program 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. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#ifndef BITMAP_H
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#define BITMAP_H
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#include <stdio.h>
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#include "bounding-box.h"
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#include "types.h"
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/* If the bitmap holds 8-bit values, rather than one-bit, the
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definition of BLACK here is wrong. So don't use it in that case! */
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#define WHITE 0
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#define BLACK 1
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/* The basic structure and macros to access it. */
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typedef struct
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{
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dimensions_type dimensions;
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one_byte *bitmap;
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} bitmap_type;
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/* The dimensions of the bitmap, in pixels. */
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#define BITMAP_DIMENSIONS(b) ((b).dimensions)
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/* The pixels, represented as an array of bytes (in contiguous storage).
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Each pixel is a single byte, even for binary fonts. */
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#define BITMAP_BITS(b) ((b).bitmap)
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/* These are convenient abbreviations for getting inside the members. */
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#define BITMAP_WIDTH(b) DIMENSIONS_WIDTH (BITMAP_DIMENSIONS (b))
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#define BITMAP_HEIGHT(b) DIMENSIONS_HEIGHT (BITMAP_DIMENSIONS (b))
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/* This is the address of the first pixel in the row ROW. */
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#define BITMAP_ROW(b, row) (BITMAP_BITS (b) + (row) * BITMAP_WIDTH (b))
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/* This is the pixel at [ROW,COL]. */
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#define BITMAP_PIXEL(b, row, col) \
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(*(BITMAP_BITS (b) + (row) * BITMAP_WIDTH (b) + (col)))
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#define BITMAP_VALID_PIXEL(b, row, col) \
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(0 <= (row) && (row) < BITMAP_HEIGHT (b) \
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&& 0 <= (col) && (col) < BITMAP_WIDTH (b))
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/* Assume that the pixel at [ROW,COL] itself is black. */
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#define BITMAP_INTERIOR_PIXEL(b, row, col) \
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(0 != (row) && (row) != BITMAP_HEIGHT (b) - 1 \
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&& 0 != (col) && (col) != BITMAP_WIDTH (b) - 1 \
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&& BITMAP_PIXEL (b, row - 1, col - 1) == BLACK \
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&& BITMAP_PIXEL (b, row - 1, col) == BLACK \
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&& BITMAP_PIXEL (b, row - 1, col + 1) == BLACK \
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&& BITMAP_PIXEL (b, row, col - 1) == BLACK \
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&& BITMAP_PIXEL (b, row, col + 1) == BLACK \
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&& BITMAP_PIXEL (b, row + 1, col - 1) == BLACK \
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&& BITMAP_PIXEL (b, row + 1, col) == BLACK \
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&& BITMAP_PIXEL (b, row + 1, col + 1) == BLACK)
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/* Allocate storage for the bits, set them all to white, and return an
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initialized structure. */
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extern bitmap_type new_bitmap (dimensions_type);
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/* Free that storage. */
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extern void free_bitmap (bitmap_type *);
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/* Make a fresh copy of BITMAP in a new structure, and return it. */
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extern bitmap_type copy_bitmap (bitmap_type bitmap);
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/* Return the pixels in the bitmap B enclosed by the bounding box BB.
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The result is put in newly allocated storage. */
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extern bitmap_type extract_subbitmap (bitmap_type b, bounding_box_type bb);
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/* Consider the dimensions of a bitmap as a bounding box. The bounding
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box returned is in bitmap coordinates, rather than Cartesian, and
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refers to pixels, rather than edges. Specifically, this means that
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the maximum column is one less than results from `dimensions_to_bb
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(BITMAP_DIMENSIONS ())'. */
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extern bounding_box_type bitmap_to_bb (const bitmap_type);
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/* Return a vector of zero-based column numbers marking transitions from
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black to white or white to black in ROW, which is of length WIDTH.
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The end of the vector is marked with an element of length WIDTH + 1.
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The first element always marks a white-to-black transition (or it's
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0, if the first pixel in ROW is black). */
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extern unsigned *bitmap_find_transitions (const one_byte *row, unsigned width);
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/* Print part of or all of a bitmap. */
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extern void print_bounded_bitmap (FILE *, bitmap_type, bounding_box_type);
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extern void print_bitmap (FILE *, bitmap_type);
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#endif /* not BITMAP_H */
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