- // VZ: as this function uses setjmp() the only fool proof error handling
- // method is to use goto (setjmp is not really C++ dtors friendly...)
-
- unsigned char **lines = (unsigned char **) NULL;
- unsigned int i;
- png_infop info_ptr = (png_infop) NULL;
-
- image->Destroy();
-
- png_structp png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING,
- (voidp) NULL,
- (png_error_ptr) NULL,
- (png_error_ptr) NULL );
- if (!png_ptr)
- goto error;
-
- info_ptr = png_create_info_struct( png_ptr );
- if (!info_ptr)
- goto error;
-
- if (setjmp(png_ptr->jmpbuf))
- goto error;
-
- if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- goto error;
-
- png_set_read_fn( png_ptr, &stream, _PNG_stream_reader);
-
- png_uint_32 width,height;
- int bit_depth,color_type,interlace_type;
-
- png_read_info( png_ptr, info_ptr );
- png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL );
-
- if (color_type == PNG_COLOR_TYPE_PALETTE)
- png_set_expand( png_ptr );
-
- png_set_strip_16( png_ptr );
- png_set_packing( png_ptr );
- if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS))
- png_set_expand( png_ptr );
- png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
-
- image->Create( width, height );
-
- if (!image->Ok())
- goto error;
-
- lines = (unsigned char **)malloc( height * sizeof(unsigned char *) );
- if (lines == NULL)
- goto error;
-
- for (i = 0; i < height; i++)
+ if ( !Ok() )
+ return wxNullBitmap;
+
+ // sizeLimit is the MS upper limit for the DIB size
+#ifdef WIN32
+ int sizeLimit = 1024*768*3;
+#else
+ int sizeLimit = 0x7fff ;
+#endif
+
+ // width and height of the device-dependent bitmap
+ int width = GetWidth();
+ int bmpHeight = GetHeight();
+
+ // calc the number of bytes per scanline and padding
+ int bytePerLine = width*3;
+ int sizeDWORD = sizeof( DWORD );
+ int lineBoundary = bytePerLine % sizeDWORD;
+ int padding = 0;
+ if( lineBoundary > 0 )
+ {
+ padding = sizeDWORD - lineBoundary;
+ bytePerLine += padding;
+ }
+ // calc the number of DIBs and heights of DIBs
+ int numDIB = 1;
+ int hRemain = 0;
+ int height = sizeLimit/bytePerLine;
+ if( height >= bmpHeight )
+ height = bmpHeight;
+ else
+ {
+ numDIB = bmpHeight / height;
+ hRemain = bmpHeight % height;
+ if( hRemain >0 ) numDIB++;
+ }
+
+ // set bitmap parameters
+ wxBitmap bitmap;
+ wxCHECK_MSG( Ok(), bitmap, wxT("invalid image") );
+ bitmap.SetWidth( width );
+ bitmap.SetHeight( bmpHeight );
+ bitmap.SetDepth( wxDisplayDepth() );
+
+ // create a DIB header
+ int headersize = sizeof(BITMAPINFOHEADER);
+ BITMAPINFO *lpDIBh = (BITMAPINFO *) malloc( headersize );
+ wxCHECK_MSG( lpDIBh, bitmap, wxT("could not allocate memory for DIB header") );
+ // Fill in the DIB header
+ lpDIBh->bmiHeader.biSize = headersize;
+ lpDIBh->bmiHeader.biWidth = (DWORD)width;
+ lpDIBh->bmiHeader.biHeight = (DWORD)(-height);
+ lpDIBh->bmiHeader.biSizeImage = bytePerLine*height;
+ // the general formula for biSizeImage:
+ // ( ( ( ((DWORD)width*24) +31 ) & ~31 ) >> 3 ) * height;
+ lpDIBh->bmiHeader.biPlanes = 1;
+ lpDIBh->bmiHeader.biBitCount = 24;
+ lpDIBh->bmiHeader.biCompression = BI_RGB;
+ lpDIBh->bmiHeader.biClrUsed = 0;
+ // These seem not really needed for our purpose here.
+ lpDIBh->bmiHeader.biClrImportant = 0;
+ lpDIBh->bmiHeader.biXPelsPerMeter = 0;
+ lpDIBh->bmiHeader.biYPelsPerMeter = 0;
+ // memory for DIB data
+ unsigned char *lpBits;
+ lpBits = (unsigned char *)malloc( lpDIBh->bmiHeader.biSizeImage );
+ if( !lpBits )
+ {
+ wxFAIL_MSG( wxT("could not allocate memory for DIB") );
+ free( lpDIBh );
+ return bitmap;
+ }
+
+ // create and set the device-dependent bitmap
+ HDC hdc = ::GetDC(NULL);
+ HDC memdc = ::CreateCompatibleDC( hdc );
+ HBITMAP hbitmap;
+ hbitmap = ::CreateCompatibleBitmap( hdc, width, bmpHeight );
+ ::SelectObject( memdc, hbitmap);
+
+ // copy image data into DIB data and then into DDB (in a loop)
+ unsigned char *data = GetData();
+ int i, j, n;
+ int origin = 0;
+ unsigned char *ptdata = data;
+ unsigned char *ptbits;
+
+ for( n=0; n<numDIB; n++ )
projects / wxWidgets.git / blobdiff