GDI + learning Record (26): Displaying images-image

//Display image  var g:tgpgraphics; Img:tgpimage;  begin G: = Tgpgraphics.create (Self.Canvas.Handle);  IMG: = tgpimage.create (' c:\temp\x.jpg '); G.drawimage (IMG,x,{parameter 2, 3 is the coordinate} img.  Free; G.free; End;

//Display images by standard height and width  var g:tgpgraphics; Img:tgpimage;  begin G: = Tgpgraphics.create (Canvas.handle); IMG: = tgpimage.create (' c:\temp\x.jpg '), IMG. GetWidth, IMG.  GetHeight); Img.  Free; G.free; End;

//Display image at specified height and width  var g:tgpgraphics; Img:tgpimage;  begin G: = Tgpgraphics.create (Canvas.handle);  IMG: = tgpimage.create (' c:\temp\x.jpg '); Img.  Free; G.free; End;

//Slightly reduced image  var g:tgpgraphics; IMG, imgsmall:tgpimage;  begin G: = Tgpgraphics.create (Canvas.handle);  img:= tgpimage.create (' c:\temp\x.jpg '); Imgsmall: = img. Getthumbnailimage (nilnil., Imgsmall.getwidth  , imgsmall.getheight); Img.  Free;  Imgsmall.free; G.free; End;

//Picture Parallelogram transformvarG:tgpgraphics; Img:tgpimage;ConstPts:Array[0..2] ofTgppoint = ((x: -; Y: -), (x: About; Y: $), (x: -; Y: the));beginG: = Tgpgraphics.create (Canvas.handle); Img:= Tgpimage.create (' c:\temp\x.jpg '); G.drawimage (IMG,0,0);{This is the original picture}G.drawimage (IMG, Pgppoint (@pts),3);{After repeated testing, the sentiment is as follows: 1, only need 3 points to control the picture, not more or less. 2, point 1 control the upper right corner; Point 2 controls the upper left corner;    Point 3 controls the lower-right corner.  3, because is parallelogram, so the left bottom corner of the point (is the upper right corner of the diagonal point) program can be calculated out. }Img.  Free; G.free;End;

//algorithm comparison for image scalingvarG:tgpgraphics;  Img:tgpimage; W, H:uint;beginG: = Tgpgraphics.create (Canvas.handle); Img:= Tgpimage.create (' c:\temp\x.jpg '); W: = img.  getwidth; H: = img.  GetHeight; G.drawimage (IMG, Makerect (Ten,Ten, W, h),0,0, W, H, Unitpixel);  G.setinterpolationmode (Interpolationmodenearestneighbor); G.drawimage (IMG, Makerect (Ten, -,0.6*w,0.6*H),0,0, W, H, Unitpixel);  G.setinterpolationmode (interpolationmodehighqualitybilinear); G.drawimage (IMG, Makerect ( Max, -,0.6*w,0.6*H),0,0, W, H, Unitpixel);  G.setinterpolationmode (interpolationmodehighqualitybicubic); G.drawimage (IMG, Makerect (290, -,0.6*w,0.6*H),0,0, W, H, Unitpixel); Img.  Free; G.free;End;

Algorithm options when zooming or rotating an image:

Delphi	Microsoft	Description
Interpolationmodebicubic	Bicubic	Specifies a double three-time interpolation method. No pre-filtering is made. This mode does not apply when the image is shrunk to less than 25% of its original size.
Interpolationmodebilinear	Bilinear	Specifies the bilinear interpolation method. No pre-filtering is made. This mode does not apply when the image is shrunk to less than 50% of its original size.
Interpolationmodedefault	Default	Specifies the default mode.
Interpolationmodehigh	High	Specifies the high-quality interpolation method.
Interpolationmodehighqualitybicubic	Highqualitybicubic	Specifies a high-quality double three-time interpolation method. Perform pre-screening to ensure high-quality shrinkage. This mode produces the highest quality conversion image.
Interpolationmodehighqualitybilinear	Highqualitybilinear	Specifies a high-quality bilinear interpolation method. Perform pre-screening to ensure high-quality shrinkage.
Interpolationmodeinvalid	Invalid	The Invalid element that is equivalent to the Qualitymode enumeration.
Interpolationmodelow	Low	Specifies a low-quality interpolation method.
Interpolationmodenearestneighbor	Nearestneighbor	Specifies the nearest interpolation method.

GDI + learning Record (26): Displaying images-image