# How To ... (VCL/LCL Classes)

# How To ... (VCL/LCL Classes)

This section shows few possible usages of VCL/LCL Imaging Classes and related functions described in VCL/LCL Classes. You can also learn how to use these classes by looking at demos which use them Pascal Demos.
Using TGraphic Imaging descendants:
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uses ImagingTypes, Imaging, ImagingClasses, // Add unit with VCL/LCL support, new file formats are automatically // registered to TPicture (so they will appear in TOpenPictureDialog for example) ImagingComponents;

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procedure Assignments; var ImgBitmap: TImagingBitmap; ImgData: TImageData; ImgClass: TBaseImage begin // Create empty Imaging bitmap ImgBitmap := TImagingBitmap.Create; // Load image from file to TImageData record and assign it to bitmap InitImage(ImgData); LoadImageFromFile('littlecat.png', ImgData); ImgBitmap.AssignFromData(ImgData); // Now create high level image class from file and assign it to bitmap // by overridden TPersistent.Assign method ImgClass := TSingleImage.CreateFromFile('notsolittlecat.png'); ImgBitmap.Assign(ImgClass); // Assign Imaging bitmap to TImage component on Form1 (it should be immediately // displayed) Form1.Image.Picture.Graphic := ImgBitmap; // Free loaded images FreeImage(ImgData); ImgClass.Free; end;
Displaying Imaging's images in VCL/LCL:
// This procedure shows given image (high level class) on form // by converting it to TBitmap and then drawing on form's canvas procedure ShowImageOnForm1(Form: TForm; Image: TBaseImage); var Bitmap: TBitmap; begin Bitmap := TBitmap.Create; // Call Imaging procedure for converting images to Graphics' TBitmap object ConvertImageToBitmap(Image, Bitmap); // Draw bitmap onto form's canvas Form.Canvas.Draw(0, 0, Bitmap); Bitmap.Free; end;

// This procedure shows given image (high level class) on form's // canvas directly without conversion so it is significantly faster // than ShowImageOnForm1. But it has a drawback: it does not work // with all image data formats. procedure ShowImageOnForm2(Form: TForm; Image: TBaseImage); begin // Call Imaging procedure for displaying images directly on canvas without // costly conversion. Drawback of this is that it supports only images in // ifA8R8G8B8 data format DisplayImage(Form.Canvas, Form.BoundsRect, Image, Image.BoundsRect); end;

// You have TBitmap and you want to save it as PNG or other file format // supported by Imaging procedure SaveBitmapAsPNG(Bitmap: TBitmap; const FileName: string); var PNG: TImagingPNG; begin PNG := TImagingPNG.Create; PNG.Assign(Bitmap); PNG.SaveToFile(FileName); PNG.Free; end;