// // "$Id$" // // WIN32 image reading routines for the Fast Light Tool Kit (FLTK). // // Copyright 1998-2010 by Bill Spitzak and others. // // This library is free software. Distribution and use rights are outlined in // the file "COPYING" which should have been included with this file. If this // file is missing or damaged, see the license at: // // http://www.fltk.org/COPYING.php // // Please report all bugs and problems on the following page: // // http://www.fltk.org/str.php // // // 'fl_read_image()' - Read an image from the current window. // uchar * // O - Pixel buffer or NULL if failed fl_read_image(uchar *p, // I - Pixel buffer or NULL to allocate int X, // I - Left position int Y, // I - Top position int w, // I - Width of area to read int h, // I - Height of area to read int alpha) { // I - Alpha value for image (0 for none) int d; // Depth of image // Allocate the image data array as needed... d = alpha ? 4 : 3; if (!p) p = new uchar[w * h * d]; // Initialize the default colors/alpha in the whole image... memset(p, alpha, w * h * d); // Grab all of the pixels in the image... // Assure that we are not trying to read non-existing data. If it is so, the // function should still work, but the out-of-bounds part of the image is // untouched (initialized with the alpha value or 0 (black), resp.). int ww = w; // We need the original width for output data line size int shift_x = 0; // X target shift if X modified int shift_y = 0; // Y target shift if X modified if (X < 0) { shift_x = -X; w += X; X = 0; } if (Y < 0) { shift_y = -Y; h += Y; Y = 0; } if (h < 1 || w < 1) return p; // nothing to copy int line_size = ((3*w+3)/4) * 4; // each line is aligned on a DWORD (4 bytes) uchar *dib = new uchar[line_size*h]; // create temporary buffer to read DIB // fill in bitmap info for GetDIBits BITMAPINFO bi; bi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER); bi.bmiHeader.biWidth = w; bi.bmiHeader.biHeight = -h; // negative => top-down DIB bi.bmiHeader.biPlanes = 1; bi.bmiHeader.biBitCount = 24; // 24 bits RGB bi.bmiHeader.biCompression = BI_RGB; bi.bmiHeader.biSizeImage = 0; bi.bmiHeader.biXPelsPerMeter = 0; bi.bmiHeader.biYPelsPerMeter = 0; bi.bmiHeader.biClrUsed = 0; bi.bmiHeader.biClrImportant = 0; // copy bitmap from original DC (Window, Fl_Offscreen, ...) HDC hdc = CreateCompatibleDC(fl_gc); HBITMAP hbm = CreateCompatibleBitmap(fl_gc,w,h); int save_dc = SaveDC(hdc); // save context for cleanup SelectObject(hdc,hbm); // select bitmap BitBlt(hdc,0,0,w,h,fl_gc,X,Y,SRCCOPY); // copy image section to DDB // copy RGB image data to the allocated DIB GetDIBits(hdc, hbm, 0, h, dib, (BITMAPINFO *)&bi, DIB_RGB_COLORS); // finally copy the image data to the user buffer for (int j = 0; j