You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
366 lines
8.3 KiB
366 lines
8.3 KiB
15 years ago
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<title>KSquirrel: development</title>
|
||
|
|
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
||
|
|
<meta name='Author' content='Baryshev Dmitry/Krasu'>
|
||
|
|
|
||
|
|
<link rel="stylesheet" href="styles.css" type="text/css">
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
|
||
|
|
<center><h3><b>How to write a new library for KSquirrel (for example, it will decode abstract 'ttx' format) ?</b></h3></center>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li>Create a directory with necessary sources ('generate' is distributed with ksquirrel-libs):
|
||
|
|
<br><br>
|
||
|
|
<table cellpadding="2" cellspacing="2" width="70%" align="center">
|
||
|
|
<tbody>
|
||
|
|
<tr>
|
||
|
|
<td valign="top" bgcolor="#CCCCCC">
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
# ./generate ttx -build
|
||
|
|
</pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
<br><br>
|
||
|
|
<li>Typical fmt_codec_ttx_defs.h
|
||
|
|
<br><br>
|
||
|
|
<table cellpadding="2" cellspacing="2" width="70%" align="center">
|
||
|
|
<tbody>
|
||
|
|
<tr>
|
||
|
|
<td valign="top" bgcolor="#CCCCCC">
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
#ifndef KSQUIRREL_READ_IMAGE_ttx
|
||
|
|
#define KSQUIRREL_READ_IMAGE_ttx
|
||
|
|
|
||
|
|
// Define constants you need here
|
||
|
|
|
||
|
|
#endif
|
||
|
|
</pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
<br><br>
|
||
|
|
<li>Typical fmt_codec_ttx.h
|
||
|
|
<br><br>
|
||
|
|
<table cellpadding="2" cellspacing="2" width="70%" align="center">
|
||
|
|
<tbody>
|
||
|
|
<tr>
|
||
|
|
<td valign="top" bgcolor="#CCCCCC">
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
#ifndef KSQUIRREL_LIBS_CLASS_DEFINITION_ttx_H
|
||
|
|
#define KSQUIRREL_LIBS_CLASS_DEFINITION_ttx_H
|
||
|
|
|
||
|
|
#include "fmt_codec_base.h"
|
||
|
|
|
||
|
|
class fmt_codec : public fmt_codec_base
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
|
||
|
|
fmt_codec();
|
||
|
|
~fmt_codec();
|
||
|
|
|
||
|
|
virtual std::string fmt_version();
|
||
|
|
virtual std::string fmt_quickinfo();
|
||
|
|
virtual std::string fmt_filter();
|
||
|
|
virtual std::string fmt_mime();
|
||
|
|
virtual std::string fmt_pixmap();
|
||
|
|
virtual std::string fmt_extension(const s32 bpp);
|
||
|
|
|
||
|
|
virtual bool fmt_readable() const;
|
||
|
|
virtual s32 fmt_read_init(const std::string &file);
|
||
|
|
virtual s32 fmt_read_next();
|
||
|
|
virtual s32 fmt_read_next_pass();
|
||
|
|
virtual s32 fmt_read_scanline(RGBA *scan);
|
||
|
|
virtual void fmt_read_close();
|
||
|
|
|
||
|
|
|
||
|
|
virtual bool fmt_writable() const;
|
||
|
|
virtual void fmt_getwriteoptions(fmt_writeoptionsabs *);
|
||
|
|
virtual s32 fmt_write_init(const std::string &file, const fmt_image &image,
|
||
|
|
const fmt_writeoptions &opt);
|
||
|
|
virtual s32 fmt_write_next();
|
||
|
|
virtual s32 fmt_write_next_pass();
|
||
|
|
virtual s32 fmt_write_scanline(RGBA *scan);
|
||
|
|
virtual void fmt_write_close();
|
||
|
|
|
||
|
|
private:
|
||
|
|
// define variables you need here
|
||
|
|
};
|
||
|
|
|
||
|
|
extern "C" fmt_codec_base* fmt_codec_create()
|
||
|
|
{
|
||
|
|
return (new fmt_codec);
|
||
|
|
}
|
||
|
|
|
||
|
|
extern "C" void fmt_codec_destroy(fmt_codec_base *p)
|
||
|
|
{
|
||
|
|
delete p;
|
||
|
|
}
|
||
|
|
</pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
<br><br>
|
||
|
|
<li>Typical fmt_codec_ttx.cpp
|
||
|
|
<br><br>
|
||
|
|
<table cellpadding="2" cellspacing="2" width="70%" align="center">
|
||
|
|
<tbody>
|
||
|
|
<tr>
|
||
|
|
<td valign="top" bgcolor="#CCCCCC">
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
|
||
|
|
#include <iostream>
|
||
|
|
|
||
|
|
#include "fmt_types.h"
|
||
|
|
#include "fileio.h"
|
||
|
|
#include "fmt_codec_ttx_defs.h"
|
||
|
|
#include "fmt_codec_ttx.h"
|
||
|
|
|
||
|
|
#include "error.h"
|
||
|
|
|
||
|
|
fmt_codec::fmt_codec() : fmt_codec_base()
|
||
|
|
{}
|
||
|
|
|
||
|
|
fmt_codec::~fmt_codec()
|
||
|
|
{}
|
||
|
|
|
||
|
|
<b>Returns library's version</b>
|
||
|
|
std::string fmt_codec::fmt_version()
|
||
|
|
{
|
||
|
|
return std::string("0.0.1");
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Returns common information on ttx format</b>
|
||
|
|
std::string fmt_codec::fmt_quickinfo()
|
||
|
|
{
|
||
|
|
return std::string("TTX is a very cool format!");
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Filter for a file manager (with a blank after
|
||
|
|
each extension)</b>
|
||
|
|
std::string fmt_codec::fmt_filter()
|
||
|
|
{
|
||
|
|
return std::string("*.ttx1 *.ttx2 *.ttx3 ");
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>The regular expression defining the file type
|
||
|
|
(usually first 2-5 characters in a file).
|
||
|
|
This example shows, that format TTX is defined by header
|
||
|
|
TTX7, TTX8 or TTX9. If the file has no header
|
||
|
|
(like .ico and .pix) this function should return empty string.</b>
|
||
|
|
std::string fmt_codec::fmt_mime()
|
||
|
|
{
|
||
|
|
return std::string("TTX[789]");
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Compile <a href='bits.html'>this program</a>,
|
||
|
|
create PNG icon 16x16 and run
|
||
|
|
#./bits icon.png > icon.bits.
|
||
|
|
Then copy contents of icon.bits here</b>
|
||
|
|
std::string fmt_codec::fmt_pixmap()
|
||
|
|
{
|
||
|
|
return std::string("");
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Open file, initialize variables, etc.</b>
|
||
|
|
s32 fmt_codec::fmt_read_init(const std::string &file)
|
||
|
|
{
|
||
|
|
frs.open(file.c_str(), ios::binary | ios::in);
|
||
|
|
|
||
|
|
if(!frs.good())
|
||
|
|
return SQERR_NOFILE;
|
||
|
|
|
||
|
|
currentImage = -1;
|
||
|
|
read_error = false;
|
||
|
|
|
||
|
|
finfo.animated = false;
|
||
|
|
|
||
|
|
return SQERR_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>This method will be called BEFORE decoding of each image in a file,
|
||
|
|
so we should seek to correct file offset or do something important now.
|
||
|
|
Return SQERR_NOTOK, if the next image can't be decoded (no such image),
|
||
|
|
and any other error code on error.</b>
|
||
|
|
s32 fmt_codec::fmt_read_next()
|
||
|
|
{
|
||
|
|
currentImage++;
|
||
|
|
|
||
|
|
if(currentImage)
|
||
|
|
return SQERR_NOTOK; <b>return, if TTX can
|
||
|
|
have only one image.</b>
|
||
|
|
|
||
|
|
fmt_image image;
|
||
|
|
|
||
|
|
<b>Non-interlaced image has 1 pass.
|
||
|
|
If you need to define another value, do it here</b>
|
||
|
|
image.passes = 1;
|
||
|
|
|
||
|
|
<b>Here you should read necessary data from file,
|
||
|
|
and initialize finfo.image[currentImage].w,h,bpp. Return error
|
||
|
|
code you need on error.</b>
|
||
|
|
<b>...</b>
|
||
|
|
|
||
|
|
image.compression = "-";
|
||
|
|
image.colorspace = "RGB";
|
||
|
|
|
||
|
|
finfo.image.push_back(image);
|
||
|
|
|
||
|
|
return SQERR_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>This method will be called BEFORE decoding of each pass
|
||
|
|
in the interlaced image.</b>
|
||
|
|
s32 fmt_codec::fmt_read_next_pass()
|
||
|
|
{
|
||
|
|
<b>Our TTX fromat can't be interlaced, so we
|
||
|
|
won't do anything, just return SQERR_OK</b>
|
||
|
|
return SQERR_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Reads scanline in 'scan'. This example just fills
|
||
|
|
'scan' with white color (RGBA(255,255,255,255))</b>
|
||
|
|
s32 fmt_codec::fmt_read_scanline(RGBA *scan)
|
||
|
|
{
|
||
|
|
memset(scan, 255, finfo.image[currentImage].w * sizeof(RGBA));
|
||
|
|
|
||
|
|
return SQERR_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Closes everything, frees allocated memory, etc.</b>
|
||
|
|
void fmt_codec::fmt_read_close()
|
||
|
|
{
|
||
|
|
frs.close();
|
||
|
|
|
||
|
|
// you should free information on close
|
||
|
|
finfo.meta.clear();
|
||
|
|
finfo.image.clear();
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Returns write options for TTX format. This method won't be
|
||
|
|
called, if fmt_writable() returns 'false'</b>
|
||
|
|
void fmt_codec::fmt_getwriteoptions(fmt_writeoptionsabs *opt)
|
||
|
|
{
|
||
|
|
<b>Can TTX format be interlaced ? No.</b>
|
||
|
|
opt->interlaced = false;
|
||
|
|
|
||
|
|
<b>With which compression it can be compressed ?
|
||
|
|
With no compression (like not-RLE BMP).</b>
|
||
|
|
opt->compression_scheme = CompressionNo;
|
||
|
|
|
||
|
|
<b>minimum, maximum, and default compression level.
|
||
|
|
Ignored, if the compression is CompressionNo.</b>
|
||
|
|
opt->compression_min = 0;
|
||
|
|
opt->compression_max = 0;
|
||
|
|
opt->compression_def = 0;
|
||
|
|
|
||
|
|
<b>TTX can't be interlaced, passes = 1</b>
|
||
|
|
opt->passes = 1;
|
||
|
|
|
||
|
|
<b>KSquirrel shouldn't flip the image
|
||
|
|
before writing</b>
|
||
|
|
opt->needflip = false;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Same to fmt_read_init()</b>
|
||
|
|
s32 fmt_codec::fmt_write_init(const std::string &file, const fmt_image &image,
|
||
|
|
const fmt_writeoptions &opt)
|
||
|
|
{
|
||
|
|
if(!image.w || !image.h || file.empty())
|
||
|
|
return SQE_W_WRONGPARAMS;
|
||
|
|
|
||
|
|
writeimage = image;
|
||
|
|
writeopt = opt;
|
||
|
|
|
||
|
|
fws.open(file.c_str(), ios::binary | ios::out);
|
||
|
|
|
||
|
|
if(!fws.good())
|
||
|
|
return SQE_W_NOFILE;
|
||
|
|
|
||
|
|
return SQE_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Same to fmt_read_next()</b>
|
||
|
|
s32 fmt_codec::fmt_write_next()
|
||
|
|
{
|
||
|
|
return SQE_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Same to fmt_read_next_pass()</b>
|
||
|
|
s32 fmt_codec::fmt_write_next_pass()
|
||
|
|
{
|
||
|
|
return SQE_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Write scanline. Same to fmt_read_scanline()</b>
|
||
|
|
s32 fmt_codec::fmt_write_scanline(RGBA *scan)
|
||
|
|
{
|
||
|
|
...
|
||
|
|
return SQE_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Same to fmt_read_init()</b>
|
||
|
|
void fmt_codec::fmt_write_close()
|
||
|
|
{
|
||
|
|
fws.close();
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Can this library write TTX ? No.</b>
|
||
|
|
bool fmt_codec::fmt_writable() const
|
||
|
|
{
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Can this library read TTX ? Yes.</b>
|
||
|
|
bool fmt_codec::fmt_readable() const
|
||
|
|
{
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
<b>Some libraries support several image types (like PNM library).
|
||
|
|
This method should be used by writing function to determine file extension by image's bpp.
|
||
|
|
For example, 1 bpp means .pbm, 8 bpp - pgm</b>"
|
||
|
|
std::string fmt_codec::fmt_extension(const s32 /*bpp*/)
|
||
|
|
{
|
||
|
|
return std::string("");
|
||
|
|
}
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
<br><br>
|
||
|
|
<li>Compile it
|
||
|
|
<br><br>
|
||
|
|
<table cellpadding="2" cellspacing="2" width="70%" align="center">
|
||
|
|
<tbody>
|
||
|
|
<tr>
|
||
|
|
<td valign="top" bgcolor="#CCCCCC">
|
||
|
|
<pre>
|
||
|
|
# ./compile-c++
|
||
|
|
#
|
||
|
|
</pre>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
<br><br>
|
||
|
|
<li>That's all. You've just created a new decoder for KSquirrel. Copy libSQ_codec_ttx.so in /usr/lib/ksquirrel-libs.
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|