GDIPlus Skewing an Image

[ChrisL]

While this works I'm not convinced its the best way to do it.

It opens an image file.

Draws (squashes)the image to a 200x200 square in memory

Then draws a skewed image for left and right.

Eventually this is for a Photo viewer and the skewed left and right image will be for previous and next image, so I will have to have it as a function that returns the individual left or right image as a bitmap in memory.

The other thing is I need to draw a box/border around the skewed image and I'm not sure the best way to go about that either.

Any help and advise please.

Thanks

Chris

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#include <GDIPlus.au3>


Global $width=500
Global $height=300
$hwnd=GUICreate("Skew",$width,$height)
GUISetState()


_GDIPlus_Startup()
$graphics=_GDIPlus_GraphicsCreateFromHWND($hwnd)
_GDIPlus_GraphicsClear($graphics,0xFF008800)
$image=_GDIPlus_ImageLoadFromFile("D:\My Documents\My Pictures\DSCF0239.JPG")
$iwidth=_GDIPlus_ImageGetWidth($image)
$iheight=_GDIPlus_ImageGetHeight($image)


$h200BMP = _GDIPlus_BitmapCreateFromGraphics(200,200, $graphics)
ConsoleWrite("200x200 BMP Handle = " & $h200BMP & @crlf)
$hGraphicsContext = _GDIPlus_ImageGetGraphicsContext ($h200BMP)
ConsoleWrite("hraphicsContext = " & $hGraphicsContext & @crlf)
$Ret = _GDIPlus_GraphicsDrawImageRectRect($hGraphicsContext,$image,20,20,$iwidth,$iheight,0,0,200,200)
ConsoleWrite("GraphicsDrawImageRectRect = " & $Ret & @crlf)
$hClone = _GDIPlus_BitmapCloneArea($h200BMP,0,0,200,200)
ConsoleWrite("BitmApCloneArea = " & $hClone & @crlf)


$topless = 40;say top is 40 shorter than bottom
$angle = 3

;Right hand Skew
for $iSrcX = 1 to 200 step $angle

    $indent = $topless*(200 - $iSrcX)/200
    ;_GDIPlus_GraphicsDrawImageRectRect($hGraphics, $hImage, $iSrcX, $iSrcY, $iSrcWidth, $iSrcHeight, $iDstX,           $iDstY,    $iDstWidth,   $iDstHeight
    _GDIPlus_GraphicsDrawImageRectRect($graphics,  $hClone,  $iSrcX ,    0 , $iSrcX + 1,    200 ,   320 +$iSrcX/$angle,  50+$indent ,   1 ,        200 - (2*$indent) )

Next


;Left hand Skew
For $iSrcX = 200 to 1 step -$angle

      $indent = $topless*(200 - $iSrcX)/200
    ;_GDIPlus_GraphicsDrawImageRectRect($hGraphics, $hImage, $iSrcX,        $iSrcY, $iSrcWidth, $iSrcHeight, $iDstX,           $iDstY,    $iDstWidth,   $iDstHeight
    _GDIPlus_GraphicsDrawImageRectRect($graphics,  $hClone,  200 - $iSrcX ,    0 ,  $iSrcX - 1,    200 ,   160-$iSrcX/$angle,  50+$indent ,   1 ,        200 - (2*$indent) )

Next


Do
Until GUIGetMsg()=-3


_GDIPlus_ImageDispose ($hClone)
_GDIPlus_BitmapDispose($h200BMP)
_GDIPlus_ImageDispose($image)
_GDIPlus_GraphicsDispose($graphics)
_GDIPlus_GraphicsDispose($hGraphicsContext)
_GDIPlus_Shutdown()

Edited August 21, 2010 by ChrisL

[UEZ]

I do not know any function in GDI+ lib. that can skew an image that way - only _GDIPlus_DrawImagePoints() but this function creates only parallelograms.

For an example of _GDIPlus_DrawImagePoints() have a look e.g. to Rotating Cube 2 + Textures where unfortunately the perspective is not properly because of parallelograms .

To draw a box I used this method:

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#include <GDIPlus.au3>


Global $width=500
Global $height=300
$hwnd=GUICreate("Skew",$width,$height)
GUISetState()


_GDIPlus_Startup()
$graphics=_GDIPlus_GraphicsCreateFromHWND($hwnd)
_GDIPlus_GraphicsClear($graphics,0xFF008800)
$image=_GDIPlus_ImageLoadFromFile("D:\My Documents\My Pictures\DSCF0239.JPG")
$iwidth=_GDIPlus_ImageGetWidth($image)
$iheight=_GDIPlus_ImageGetHeight($image)
$hPen=_GDIPlus_PenCreate(0xF0202060,16) ;create a pen

$h200BMP = _GDIPlus_BitmapCreateFromGraphics(200,200, $graphics)
ConsoleWrite("200x200 BMP Handle = " & $h200BMP & @crlf)
$hGraphicsContext = _GDIPlus_ImageGetGraphicsContext ($h200BMP)
_GDIPlus_GraphicsSetSmoothingMode($hGraphicsContext, 2)

ConsoleWrite("hraphicsContext = " & $hGraphicsContext & @crlf)
$Ret = _GDIPlus_GraphicsDrawImageRectRect($hGraphicsContext,$image,0,0,$iwidth,$iheight,0,0,200,200)
_GDIPlus_GraphicsDrawRect($hGraphicsContext,0,0,200,200,$hPen) ;and draw a rect. over the image


ConsoleWrite("GraphicsDrawImageRectRect = " & $Ret & @crlf)
$hClone = _GDIPlus_BitmapCloneArea($h200BMP,0,0,200,200)
ConsoleWrite("BitmApCloneArea = " & $hClone & @crlf)


$topless = 40;say top is 40 shorter than bottom
$angle = 3

;Right hand Skew
for $iSrcX = 1 to 200 step $angle

    $indent = $topless*(200 - $iSrcX)/200
    ;_GDIPlus_GraphicsDrawImageRectRect($hGraphics, $hImage, $iSrcX, $iSrcY, $iSrcWidth, $iSrcHeight, $iDstX,   $iDstY, $iDstWidth, $iDstHeight
    _GDIPlus_GraphicsDrawImageRectRect($graphics, $hClone, $iSrcX , 0 , $iSrcX + 1, 200 , 320 +$iSrcX/$angle, 50+$indent , 1 ,  200 - (2*$indent) )

Next


;Left hand Skew
For $iSrcX = 200 to 1 step -$angle

    $indent = $topless*(200 - $iSrcX)/200
    ;_GDIPlus_GraphicsDrawImageRectRect($hGraphics, $hImage, $iSrcX,    $iSrcY, $iSrcWidth, $iSrcHeight, $iDstX,    $iDstY, $iDstWidth, $iDstHeight
    _GDIPlus_GraphicsDrawImageRectRect($graphics, $hClone, 200 - $iSrcX ,   0 , $iSrcX - 1, 200 , 160-$iSrcX/$angle, 50+$indent , 1 ,   200 - (2*$indent) )

Next


Do
Until GUIGetMsg()=-3

_GDIPlus_PenDispose($hPen)
_GDIPlus_ImageDispose ($hClone)
_GDIPlus_BitmapDispose($h200BMP)
_GDIPlus_ImageDispose($image)
_GDIPlus_GraphicsDispose($graphics)
_GDIPlus_GraphicsDispose($hGraphicsContext)
_GDIPlus_Shutdown()

Maybe some GDI+ cracks may have a fast solution...

Br,

UEZ

[ChrisL]

Ahh I see cunning, you drew the box on the square image.

Thanks for the reply

[ChrisL]

I have this working quite well now..

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#include <GDIPlus.au3>


Global $width=550
Global $height=700

$hwnd=GUICreate("Skew",$width,$height)

GUISetState()


_GDIPlus_Startup()
$hgraphics=_GDIPlus_GraphicsCreateFromHWND($hwnd)
_GDIPlus_GraphicsClear($hgraphics)


_SkewImage("D:\My Documents\My Pictures\DSCF0239.JPG",360,50,$hgraphics,"Right",120,600,60)
_SkewImage("D:\My Documents\My Pictures\DSCF0239.JPG",60,50,$hgraphics,"Left",120,600,60)

Do
Until GUIGetMsg()=-3


_GDIPlus_GraphicsDispose($hGraphics)
_GDIPlus_Shutdown()




Func _SkewImage($sPath,$DrawX, $DrawY, $graphics, $Left_Or_Right, $SkewWidth = 300, $SkewHeight = 300,  $AnglePixels = 40, $BorderWidth = 5 )

    Local $SkewHImage, $SkewImageWidth, $SkewImageHeight, $hSkewPen, $hSkewBMP, $Ret, $hSkewClone, $indent

    $SkewHImage=_GDIPlus_ImageLoadFromFile($sPath)
    $SkewImageWidth=_GDIPlus_ImageGetWidth($SkewHImage)
    $SkewImageHeight=_GDIPlus_ImageGetHeight($SkewHImage)
    $hSkewPen =_GDIPlus_PenCreate(0xFFFFFFFF,$BorderWidth)

    $hSkewBMP = _GDIPlus_BitmapCreateFromGraphics($SkewWidth,$SkewHeight, $graphics)
    ConsoleWrite("200x200 BMP Handle = " & $hSkewBMP & @crlf)
    $hSkewGraphicsContext = _GDIPlus_ImageGetGraphicsContext ($hSkewBMP)
    _GDIPlus_GraphicsSetSmoothingMode($hSkewGraphicsContext, 2)

    ConsoleWrite("hraphicsContext = " & $hSkewGraphicsContext & @crlf)
    $Ret = _GDIPlus_GraphicsDrawImageRectRect($hSkewGraphicsContext,$SkewHImage,0,0,$SkewImageWidth,$SkewImageHeight,0,0,$SkewWidth,$SkewHeight)
    If $BorderWidth > 0 then _GDIPlus_GraphicsDrawRect($hSkewGraphicsContext,0,0,$SkewWidth,$SkewHeight,$hSkewPen) ;and draw a rect. over the image


    ConsoleWrite("GraphicsDrawImageRectRect = " & $Ret & @crlf)
    $hSkewClone = _GDIPlus_BitmapCloneArea($hSkewBMP,0,0,$SkewWidth,$SkewHeight)
    ConsoleWrite("BitmApCloneArea = " & $hSkewClone & @crlf)


    If $Left_Or_Right = "Right" then
        for $iSrcX = 1 to $SkewWidth step 1

            $indent = $AnglePixels*($SkewWidth - $iSrcX)/$SkewWidth

            ;_GDIPlus_GraphicsDrawImageRectRect($hGraphics,$hImage, $iSrcX, $iSrcY, $iSrcWidth, $iSrcHeight,        $iDstX,             $iDstY,    $iDstWidth, $iDstHeight
            _GDIPlus_GraphicsDrawImageRectRect($graphics, $hSkewClone,  $iSrcX ,  0 ,   $iSrcX + 1, $SkewHeight , $DrawX +$iSrcX, $DrawY+$indent , 1 ,        $SkewHeight - (2*$indent) )
            ;Sleep(1)
        Next
    Else

        For $iSrcX = 1 to $SkewWidth step 1

            $indent = -($AnglePixels*($SkewWidth - $iSrcX)/$SkewWidth - $AnglePixels)
            ConsoleWrite($indent & @crlf)
            ;_GDIPlus_GraphicsDrawImageRectRect($hGraphics, $hImage,    $iSrcX, $iSrcY, $iSrcWidth,  $iSrcHeight,          $iDstX,                 $iDstY,    $iDstWidth,   $iDstHeight
            _GDIPlus_GraphicsDrawImageRectRect($graphics, $hSkewClone,  $iSrcX ,  0 ,   $iSrcX + 1, $SkewHeight , $DrawX + $iSrcX,  $DrawY + $indent , 1 ,        $SkewHeight - (2*$indent) )
            ;_GDIPlus_GraphicsDrawImageRectRect($graphics, $hSkewClone,  $iSrcX ,   0 ,  $iSrcX + 1,  $SkewHeight ,   $DrawX + ($iSrcX/$Step), ($DrawY*2)-$indent , 1 ,   $SkewHeight - (2*$indent)  )
        ;sleep(10)
        Next

    EndIf

    _GDIPlus_PenDispose($hSkewPen)
    _GDIPlus_ImageDispose ($hSkewClone)
    _GDIPlus_BitmapDispose($hSkewBMP)
    _GDIPlus_ImageDispose($SkewHImage)
    _GDIPlus_GraphicsDispose($hSkewGraphicsContext)

EndFunc

[ChrisL]

This is what it looks like if anyone is interested