hedgewars/PNGh.pas
author unc0rr
Sun, 02 Dec 2012 01:25:11 +0400
changeset 8178 8bd087478b48
parent 6893 69cc0166be8d
child 8685 c0e54583296e
permissions -rw-r--r--
Fix QSettings problems: - Reopen file in ReadOnly mode if it was open in ReadWrite mode and is being read. This is needed for stupid QSettings which opens file in ReadWrite mode just to call readAll() on it. - Implement setSize(0)

(*
 * Hedgewars, a free turn based strategy game
 * Copyright (c) 2004-2012 Andrey Korotaev <unC0Rr@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 *)

{$INCLUDE "options.inc"}

unit PNGh;
interface

uses png;

{$IFDEF FPC}
    {$PACKRECORDS C}
{$ELSE}
    {$DEFINE cdecl attribute(cdecl)}
{$ENDIF}

const
    // Constants for libpng, they are not defined in png unit.
    // We actually don't need all of them.

    // These describe the color_type field in png_info.
    // color type masks
    PNG_COLOR_MASK_PALETTE = 1;
    PNG_COLOR_MASK_COLOR   = 2;
    PNG_COLOR_MASK_ALPHA   = 4;

    // color types.  Note that not all combinations are legal
    PNG_COLOR_TYPE_GRAY       = 0;
    PNG_COLOR_TYPE_PALETTE    = PNG_COLOR_MASK_COLOR or PNG_COLOR_MASK_PALETTE;
    PNG_COLOR_TYPE_RGB        = PNG_COLOR_MASK_COLOR;
    PNG_COLOR_TYPE_RGB_ALPHA  = PNG_COLOR_MASK_COLOR or PNG_COLOR_MASK_ALPHA;
    PNG_COLOR_TYPE_GRAY_ALPHA = PNG_COLOR_MASK_ALPHA;

    // aliases
    PNG_COLOR_TYPE_RGBA = PNG_COLOR_TYPE_RGB_ALPHA;
    PNG_COLOR_TYPE_GA   = PNG_COLOR_TYPE_GRAY_ALPHA;

    // This is for compression type. PNG 1.0-1.2 only define the single type.
    PNG_COMPRESSION_TYPE_BASE    = 0; // Deflate method 8, 32K window
    PNG_COMPRESSION_TYPE_DEFAULT = PNG_COMPRESSION_TYPE_BASE;

    // This is for filter type. PNG 1.0-1.2 only define the single type.
    PNG_FILTER_TYPE_BASE        = 0;  // Single row per-byte filtering
    PNG_INTRAPIXEL_DIFFERENCING = 64; // Used only in MNG datastreams
    PNG_FILTER_TYPE_DEFAULT     = PNG_FILTER_TYPE_BASE;

    // These are for the interlacing type.  These values should NOT be changed.
    PNG_INTERLACE_NONE  = 0; // Non-interlaced image
    PNG_INTERLACE_ADAM7 = 1; // Adam7 interlacing
    PNG_INTERLACE_LAST  = 2; // Not a valid value

type
    // where is better place for this definition?
    PFile = ^file;

procedure png_init_pascal_io(png_ptr: png_structp; pf : PFile);

implementation

// We cannot get c-style FILE* pointer to pass it to libpng, so we implement our own writing functions
procedure PngWriteData(png_ptr: png_structp; p: PByte; len: png_size_t); cdecl;
begin
    BlockWrite( PFile(png_get_io_ptr(png_ptr))^, p^, len);
end;

procedure PngFlushData(png_ptr: png_structp); cdecl;
begin
end;

procedure png_init_pascal_io(png_ptr: png_structp; pf : PFile);
begin
    png_set_write_fn(png_ptr, pf, @PngWriteData, @PngFlushData);
end;

end.