stretch_painter.cpp

// stretch_painter.cpp

// Copyright (C) 2004 Steven Weiß (steven11@gmx.de)
//
// Permission to copy, use, sell and distribute this software is granted
// provided this copyright notice appears in all copies.
// Permission to modify the code and to distribute modified code is granted
// provided this copyright notice appears in all copies, and a notice
// that the code was modified is included with the copyright notice.
//
// This software is provided "as is" without express or implied warranty,
// and with no claim as to its suitability for any purpose.


#include <background_wnd/painters/stretch_painter.hpp>
#include <background_wnd/painters/transparent_painter.hpp>


namespace win32 { namespace gui {

namespace detail {
     // ========================================================================================================= //
     // helper painter for stretch_painter which stretches the image

     class stretch_painter_helper : public painter_base
     {
          HDC hPainterDC_;    
          SIZE orig_size_;

     public:
          typedef HDC param0; 
          typedef SIZE param1;

          stretch_painter_helper(HDC hPainterDC, SIZE orig_size)
               : hPainterDC_(hPainterDC), orig_size_(orig_size)
          {}

          stretch_painter_helper* clone() const
          {
               return new stretch_painter_helper(*this);
          }

          void draw(HDC hDC, int cx, int cy)
          {
               // stretch image
               StretchBlt(hDC, 0, 0, cx, cy, hPainterDC_, 0, 0, orig_size_.cx, orig_size_.cy, SRCCOPY);       
          }
     };

}    // namespace detail

// ========================================================================================================= //
// stretch_painter

stretch_painter::stretch_painter(param0 rc_stretch, param1 cr_not_used) : rc_stretch_(rc_stretch), cr_not_used_(cr_not_used)
{}

stretch_painter* stretch_painter::clone() const
{
     return new stretch_painter(*this);
}

void stretch_painter::draw(HDC hDC, int cx, int cy)
{    
     if (cx <= 0 || cy <= 0 || rc_stretch_.width() == 0 || rc_stretch_.height() == 0 || cx < rc_stretch_.left || cy < rc_stretch_.top)
          return;

     if (painter_available()) {
          // create the memory dc
          HDC hPainterDC  = CreateCompatibleDC(hDC);                  
          HBITMAP hBmp    = CreateCompatibleBitmap(hDC, cx, cy);      
          HBITMAP hOldBmp = (HBITMAP) SelectObject(hPainterDC, hBmp);      
                              
          // fill with color not used in the adapted painter
          RECT rc = { 0, 0, cx, cy };
          HBRUSH hbr = CreateSolidBrush(cr_not_used_);
          FillRect(hPainterDC, &rc, hbr);
          DeleteObject(hbr);

          // draw the painter
          painter_base& painter = get_painter();
          painter.draw(hPainterDC, cx, cy);       
          
          // if the painter is opaque we can safely stretch it
          if (painter.is_opaque(cx, cy)) {
               StretchBlt(hDC, rc_stretch_.left, rc_stretch_.top, rc_stretch_.width(), rc_stretch_.height(), 
                            hPainterDC, 0, 0, cx, cy, SRCCOPY);       
          }
          // painter isn't opaque. we must be aware that the transparent background is cut
          else {
               // - the image is stretched in stretch_painter_helper::draw()         
               // - set the viewport origin to the position of the drawing-rectangle to trick transparent_painter ;-)
               // - after the stretching transparent_painter does the dirty job of drawing
               //    the background transparently ;-)
               POINT pt;
               SetViewportOrgEx(hDC, rc_stretch_.left, rc_stretch_.top, &pt);
               transparent_painter p(cr_not_used_);
               p.set_painter<detail::stretch_painter_helper> (hPainterDC, wnd_size(cx, cy));
               p.draw(hDC, rc_stretch_.width(), rc_stretch_.height());          
               SetViewportOrgEx(hDC, pt.x, pt.y, NULL);
          }
                    
          // clean up
          SelectObject(hPainterDC, hOldBmp);      
          DeleteObject(hBmp);      
          DeleteDC(hPainterDC);                   
     }
}

void stretch_painter::stretched_rect(const rectangle& rc_stretch)
{
     rc_stretch_  = rc_stretch;
}

rectangle stretch_painter::stretched_rect() const
{
     return rc_stretch_;
}

} }  // namespace win32::gui

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