=====Displaying a PNG or TIFF image=====

//by Richard Russell, November 2010, amended January 2012//\\ \\  BBC BASIC for Windows provides the [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin8.html#display|*DISPLAY]] command to display on the screen an image contained in a **BMP** file, and the main [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwine.html#gifjpeg|Help documentation]] describes how to display a **GIF** or **JPEG** image. If you want to display a **PNG** or **TIFF** image you can use the code listed below:

<code bb4w>
        DEF PROCdisplay(pic$, xpos%, ypos%, xsize%, ysize%)
        LOCAL tSI{}, pic%, gdip%, image%, ix%, iy%, gfx%, lGDIP%
        DIM pic% LOCAL 513

        SYS "MultiByteToWideChar", 0, 0, pic$, -1, pic%, 256

        SYS "LoadLibrary", "GDIPLUS.DLL" TO gdip%
        IF gdip% = 0 ERROR 100, "Couldn't load GDIPLUS.DLL"
        SYS "GetProcAddress", gdip%, "GdiplusStartup" TO `GdiplusStartup`
        SYS "GetProcAddress", gdip%, "GdipLoadImageFromFile" TO `GdipLoadImageFromFile`
        SYS "GetProcAddress", gdip%, "GdipDrawImageRectRectI" TO `GdipDrawImageRectRectI`
        SYS "GetProcAddress", gdip%, "GdipGetImageHeight" TO `GdipGetImageHeight`
        SYS "GetProcAddress", gdip%, "GdipGetImageWidth" TO `GdipGetImageWidth`
        SYS "GetProcAddress", gdip%, "GdipCreateFromHDC" TO `GdipCreateFromHDC`
        SYS "GetProcAddress", gdip%, "GdipSetSmoothingMode" TO `GdipSetSmoothingMode`
        SYS "GetProcAddress", gdip%, "GdipDeleteGraphics" TO `GdipDeleteGraphics`
        SYS "GetProcAddress", gdip%, "GdipDisposeImage" TO `GdipDisposeImage`
        SYS "GetProcAddress", gdip%, "GdiplusShutdown" TO `GdiplusShutdown`

        DIM tSI{GdiplusVersion%, DebugEventCallback%, \
        \       SuppressBackgroundThread%, SuppressExternalCodecs%}
        tSI.GdiplusVersion% = 1

        SYS `GdiplusStartup`, ^lGDIP%, tSI{}, 0
        SYS `GdipLoadImageFromFile`, pic%, ^image%
        IF image% = 0 THEN
          SYS `GdiplusShutdown`, lGDIP%
          SYS "FreeLibrary", gdip%
          ERROR 90, "Couldn't load " + pic$
        ENDIF

        SYS `GdipGetImageWidth`, image%, ^ix%
        SYS `GdipGetImageHeight`, image%, ^iy%

        SYS `GdipCreateFromHDC`, @memhdc%, ^gfx%
        IF gfx%=0 ERROR 90, "GdipCreateFromHDC failed"
        SYS `GdipSetSmoothingMode`, gfx%, 2

        SYS `GdipDrawImageRectRectI`, gfx%, image%, xpos%, ypos%, xsize%, ysize%, \
        \                                           0, 0, ix%, iy%, 2, 0, 0, 0

        SYS `GdipDeleteGraphics`, gfx%
        SYS `GdipDisposeImage`, image%
        SYS `GdiplusShutdown`, lGDIP%
        SYS "FreeLibrary", gdip%
        SYS "InvalidateRect", @hwnd%, 0, 0
        SYS "UpdateWindow", @hwnd%
        ENDPROC
</code>

The parameters are the path/filename of the image file, and the required position and size of the displayed image (measured in pixels from the top left-hand corner of the output window's client area).\\ \\  This code will also display **BMP**, **GIF** and **JPEG** images, and may do so with a better quality than the other methods. However it relies on the presence of the //GDI Plus// library so will work only on Windows XP (or later) or if you have specifically installed **GDIPLUS.DLL** on the target computer. Microsoft permits you to redistribute this file so you can include it with your program if necessary.