// Initialize png_ptr structure, and allocate any memory needed
public static png_struct png_create_write_struct()
{
try
{
png_struct png_ptr = new png_struct();
try
{
// initialize zbuf-compression buffer
png_ptr.zbuf_size = PNG.ZBUF_SIZE;
png_ptr.zbuf = new byte[png_ptr.zbuf_size];
png_ptr.png_set_filter_heuristics(PNG_FILTER_HEURISTIC.DEFAULT, 1, null, null);
}
catch (Exception)
{
png_ptr.zbuf = null;
png_ptr = null;
return(null);
}
return(png_ptr);
}
catch (Exception)
{
return(null);
}
}
// Create a PNG structure for reading, and allocate any memory needed.
public static png_struct png_create_read_struct()
{
try
{
png_struct png_ptr = new png_struct();
try
{
// initialize zbuf - compression buffer
png_ptr.zbuf_size = PNG.ZBUF_SIZE;
png_ptr.zbuf = new byte[png_ptr.zbuf_size];
switch (zlib.inflateInit(png_ptr.zstream))
{
case zlib.Z_OK: break;
case zlib.Z_MEM_ERROR:
case zlib.Z_STREAM_ERROR: throw new PNG_Exception("zlib memory error");
default: throw new PNG_Exception("Unknown zlib error");
}
png_ptr.zstream.out_buf = png_ptr.zbuf;
png_ptr.zstream.next_out = 0;
png_ptr.zstream.avail_out = png_ptr.zbuf_size;
}
catch (Exception)
{
png_ptr.zbuf = null;
png_ptr = null;
}
return(png_ptr);
}
catch (Exception)
{
return(null);
}
}
// Create a PNG structure for reading, and allocate any memory needed.
public static png_struct png_create_read_struct()
{
try
{
png_struct png_ptr=new png_struct();
try
{
// initialize zbuf - compression buffer
png_ptr.zbuf_size=PNG.ZBUF_SIZE;
png_ptr.zbuf=new byte[png_ptr.zbuf_size];
switch(zlib.inflateInit(png_ptr.zstream))
{
case zlib.Z_OK: break;
case zlib.Z_MEM_ERROR:
case zlib.Z_STREAM_ERROR: throw new PNG_Exception("zlib memory error");
default: throw new PNG_Exception("Unknown zlib error");
}
png_ptr.zstream.out_buf=png_ptr.zbuf;
png_ptr.zstream.next_out=0;
png_ptr.zstream.avail_out=png_ptr.zbuf_size;
}
catch(Exception)
{
png_ptr.zbuf=null;
png_ptr=null;
}
return png_ptr;
}
catch(Exception)
{
return null;
}
}
// Initialize png_ptr structure, and allocate any memory needed
public static png_struct png_create_write_struct()
{
try
{
png_struct png_ptr=new png_struct();
try
{
// initialize zbuf-compression buffer
png_ptr.zbuf_size=PNG.ZBUF_SIZE;
png_ptr.zbuf=new byte[png_ptr.zbuf_size];
png_ptr.png_set_filter_heuristics(PNG_FILTER_HEURISTIC.DEFAULT, 1, null, null);
}
catch(Exception)
{
png_ptr.zbuf=null;
png_ptr=null;
return null;
}
return png_ptr;
}
catch(Exception)
{
return null;
}
}
