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Skia4Delphi is an open-source, cross-platform 2D graphics library for Delphi, utilizing the esteemed Google's Skia library.

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About

Skia is an exceptional open-source library dedicated to rendering 2D text, geometries and images, with a focus on precision, superior quality and high performance. It offers versatile APIs compatible with a wide range of hardware and software platforms.

Google's Skia Graphics Library functions as the graphics engine for numerous products, including Google Chrome, Chrome OS, Android, Flutter, Xamarin, Mozilla Firefox, Firefox OS, and more.

Features

• Canvas 2D and Text Layout;
• CPU software rasterization;
• GPU-accelerated rendering;
• Right-to-Left rendering;
• SVG rendering and creation;
• PDF output;
• Runtime effects;
• Shading language;
• Shaders, mask and color filters;
• Image and path effects;
• Animated image player; (Lottie, GIF, WebP)
• Image codecs; (bmp, gif, ico, jpg, png, wbmp, webp and raw images) and much more...

FMX render replacement

Using the Skia4Delphi library it is possible to override Firemonkey's graphic engine so that it can use Skia as its default Canvas. With that, your Firemonkey application will automatically:

• Draw with antialiasing on any platform (the drawing quality is based on the Form.Quality property);
• Increase the overall graphics performance of your application by up to 50% (even drawing with higher quality);
• Resize images with better quality (also based on Form.Quality);
• Support Right-To-Left text rendering;
• Fix dozens of inconsistencies in drawings (especially in corners and strokes, such as dashes, and in texts with special emojis);
• Increase the performance of the library in general (controls, drawings, among others...).

Learn more...

Summary

• Using the library
  • Prerequisites
    • Install
    • Enable Skia
  • Examples
    • Basic usage
    • PDF
    • Codecs
• Integration with Delphi
  • Bitmap
  • Image formats
  • FMX Render
    • Enable Skia Render
    • Benchmark
    • Skia canvas
    • Right-to-Left
    • Custom fonts
• Controls VCL/FMX
  • TSkAnimatedImage
  • TSkLabel
  • TSkPaintBox
  • TSkSvg
    • Limitations
• Compatibility
• Known issues
  • Universal macOS Binary
  • Submit your app to the Mac App Store
• Documentation
• Version

Using the library

Prerequisites

Install

You can install Skia4Delphi in 3 ways:

• Setup (recommended)

  Download the setup of latest release and install it.

  <p><img src="Assets/Documents/installation.png" width="511" alt="Skia4Delphi Installation" /></p>

• Embarcadero's GetIt (RAD Studio > Tools > GetIt Package Manager...)

  <p><img src="https://user-images.githubusercontent.com/11139086/214978288-11c87e9e-7a8b-4686-82c0-5922676d26df.png#gh-light-mode-only" width="511" alt="GetIt" /></p> <p><img src="https://user-images.githubusercontent.com/11139086/214978346-c67bb0f6-ec96-4833-a1e4-7ee39d620e82.png#gh-dark-mode-only" width="511" alt="GetIt" /></p>

• Chocolatey package manager

  choco install skia4delphi
  

Remarks

1. Manual installation is possible, although it is not recommended; Learn more...
2. The pre-built Skia binaries were included in the source, but you can easily recompile them; Learn more...

Enable Skia

After install the Skia4Delphi, just right click in your application project and click Enable Skia.

Tip

To improve the quality and performance of FMX drawings, the replacement of the the FMX graphics engine with the Skia4Delphi render is automatically enabled. Learn more...

Examples

In this section you will find some examples of using Skia4Delphi, it works in Console, FMX, and VCL applications. The code below is common code among all the examples in this section:

uses
  System.Skia;

type
  TSkDrawExampleProc = reference to procedure(const ACanvas: ISkCanvas; const ADest: TRectF);

procedure DrawExample(const AWidth, AHeight: Integer; const ADrawProc: TSkDrawExampleProc);
begin
  var LSurface := TSkSurface.MakeRaster(AWidth, AHeight);
  LSurface.Canvas.Clear(TAlphaColors.Null);
  ADrawProc(LSurface.Canvas, RectF(0, 0, AWidth, AHeight));
  LSurface.MakeImageSnapshot.EncodeToFile('output.png');
end;

Basic usage

The code below demonstrate how to draw shapes:

DrawExample(256, 256,
  procedure (const ACanvas: ISkCanvas; const ADest: TRectF)
  begin
    var LPaint: ISkPaint := TSkPaint.Create;
    LPaint.AntiAlias := True;

    LPaint.Color := $FF4285F4;
    var LRect := TRectF.Create(PointF(10, 10), 100, 160);
    ACanvas.DrawRect(LRect, LPaint);

    var LOval: ISkRoundRect := TSkRoundRect.Create;
    LOval.SetOval(LRect);
    LOval.Offset(40, 80);
    LPaint.Color := $FFDB4437;
    ACanvas.DrawRoundRect(LOval, LPaint);

    LPaint.Color := $FF0F9D58;
    ACanvas.DrawCircle(180, 50, 25, LPaint);

    LRect.Offset(80, 50);
    LPaint.Color := $FFF4B400;
    LPaint.Style := TSkPaintStyle.Stroke;
    LPaint.StrokeWidth := 4;
    ACanvas.DrawRoundRect(LRect, 10, 10, LPaint);
  end);

This code results in the output below:

Learn more...

PDF

With Skia4Delphi it is possible to create PDF documents and draw anything on them, from text to images. The example below demonstrates how to create an PDF document and draw an SVG inside it:

  var LSVGDOM := TSkSVGDOM.MakeFromFile('Samples\Demo\Assets\lion.svg');
  var LSize := TSizeF.Create(600, 600);
  LSVGDOM.SetContainerSize(LSize);

  var LDocumentStream := TFileStream.Create('output.pdf', fmCreate);
  try
    var LDocument := TSkDocument.MakePDF(LDocumentStream);
    try
      var LCanvas := LDocument.BeginPage(LSize.Width, LSize.Height);
      try
        // Draw anything here with Skia canvas
        LSVGDOM.Render(LCanvas);
      finally
        LDocument.EndPage;
      end;
    finally
      LDocument.Close;
    end;
  finally
    LDocumentStream.Free;
  end;

This code results in the output below:

Codecs

The Skia4Delphi library supports many image formats. See below the list:

• Supported formats for decoding

  Image Format	Extensions
  Bitmap	.bmp
  GIF	.gif
  Icon	.ico
  JPEG	.jpg, .jpeg
  PNG	.png
  Raw Adobe DNG Digital Negative	.dng
  Raw Canon	.cr2
  Raw Fujifilm RAF	.raf
  Raw Nikon	.nef, .nrw
  Raw Olympus ORF	.orf
  Raw Panasonic	.rw2
  Raw Pentax PEF	.pef
  Raw Samsung SRW	.srw
  Raw Sony	.arw
  WBMP	.wbmp
  WebP	.webp

  Note: Raw images are limited to non-windows platforms

• Supported formats for encoding

  Image Format	Extensions
  JPEG	.jpg, .jpeg
  PNG	.png
  WebP	.webp

About WebP

WebP is a modern image format that provides superior lossless and lossy compression for images. WebP lossless images are 26% smaller in size compared to PNGs. WebP lossy images are 25-34% smaller than comparable JPEG images at equivalent quality.

The example below demonstrates how to encoder to WebP format:

  var LImage := TSkImage.MakeFromEncodedFile('Samples\Demo\Assets\kung-fu-panda.png');
  LImage.EncodeToFile('output.webp', TSkEncodedImageFormat.WEBP, 80);
  LImage.EncodeToFile('output.jpg', TSkEncodedImageFormat.JPEG, 80);

This code results in the output below:

Integration with Delphi

Bitmap

It is possible to edit TBitmap (VCL or FMX) with Skia's canvas using the code below:

uses
  System.Skia, FMX.Skia {or Vcl.Skia};

...

  var LBitmap := TBitmap.Create(100, 100);
  try
    LBitmap.SkiaDraw(
      procedure (const ACanvas: ISkCanvas)
      begin
        // Draw with Skia canvas...
      end);

Image formats

The library registers the following codecs:

• VCL: .svg, .webp, .wbmp and raw images (.arw, .cr2, .dng, .nef, .nrw, .orf, .raf, .rw2, .pef and .srw).

• FMX: .bmp, .gif, .ico, .webp, .wbmp and raw images (.arw, .cr2, .dng, .nef, .nrw, .orf, .raf, .rw2, .pef and .srw).

As a result, any Delphi control, such as a TImage, can normally load these new formats automatically.

FMX Render

It is possible to replace the default Canvas from FMX to Skia based Canvas. Once this feature is enabled, all FMX controls will be painted internally using Skia4Delphi automatically. With that it is possible to improve the quality and performance of the drawings throughout the FMX app, as well as generating better integration with other library features.

Enable Skia Render

Open the source of your Delphi Application Project (.dpr), include the FMX.Skia unit right after the FMX.Forms unit, and set the GlobalUseSkia to True, as in the example below:

uses
  System.StartUpCopy,
  FMX.Forms,
  FMX.Skia,
  Unit1 in 'Unit1.pas' {Form1};

{$R *.res}

begin
  GlobalUseSkia := True;
  Application.Initialize;
  ...

Remarks

1. FMX.Skia unit must be included right after the FMX.Forms;
2. The Skia Metal render can be used by including the FMX.Types unit right after the FMX.Forms unit, and setting GlobalUseMetal to True together with GlobalUseSkia to improve the speed in iOS and macOS;
3. The Skia Vulkan render can be used on RAD Studio 12 Athens or newer by including the FMX.Types unit right after the FMX.Forms unit, and setting GlobalUseVulkan to True together with GlobalUseSkia to improve the speed on Android and Windows. On Windows, Vulkan will only be used if you also add GlobalUseSkiaRasterWhenAvailable := False;;
4. This declaration of GlobalUseSkia := True;, as well as other variables of FMX itself, such as GlobalUseMetal, can also be made in the initialization of some unit instead of .dpr. Sometimes this is really necessary because if in the initialization or in the class constructor of some unit, bitmaps are used, the GlobalUseXXX declarations of the .dpr will have no effect. In this case, just create a unit in the project like "Project.Startup.pas", place the GlobalUseXXX declarations in the initialization of this new unit, and declare this new unit before any other unit of yours in the .dpr, that is, right after FMX.Forms.

Benchmark

The performance test is a simulation of a real application, with hundreds of controls, to measure the FPS rate when sliding a vertical scroll.

Metal

Remarks

1. Default FMX renderer does not use anti-aliasing on some platforms (like on mobile) while Skia Render uses it. That is, Skia has better performance and quality in the drawings than default FMX Render.

   FMX default	FMX with Skia render

2. On macOS Skia4Delphi's default renderer does not have GPU acceleration. Therefore, it is highly recommended to use Skia Metal (combining the activation of GlobalUseSkia and GlobalUseMetal), to get the full performance of the machine.

3. Tests made from virtual machines are inconsistent with reality.

Skia canvas

Using Skia's Render, during the Scene of a Bitmap, Control or Form, it is possible to access the Skia canvas property as follows:

In Bitmaps

uses
  System.Skia, FMX.Skia.Canvas;

begin
  var LBitmap := TBitmap.Create(300, 300);
  try
    LBitmap.Canvas.BeginScene;
    try
      var LCanvas: ISkCanvas := TSkCanvasCustom(LBitmap.Canvas).Canvas;
      // Draw using Skia canvas (LCanvas) directly to unlock new features...
    finally
      LBitmap.Canvas.EndScene;
    end;
  finally
    LBitmap.Free;
  end;
end;

In Controls & Forms

type
  TMyControl = class(TControl)
  protected
    procedure Paint; override;
  end;

implementation

uses
  System.Skia, FMX.Skia.Canvas;

procedure TMyControl.Paint;
begin
  var LCanvas: ISkCanvas := TSkCanvasCustom(Canvas).Canvas;
  // Draw using Skia canvas (LCanvas) directly to unlock new features...
end;

Remarks

1. Canvas property will only be available during Scene, that is, between the BeginScene and EndScene of the Bitmaps, and during paint events/methods for Controls and Forms (such as OnPaint, OnPainting, PaintChildren, among others);
2. Canvas for UI (created from a window eg TRectangles, TCircles, objects inherited from TControl) must draw exclusively from the main thread, while Canvas created from TBitmap are thread safe.

Right-to-Left

Using Skia's render, your application will now support Right-To-Left text rendering. But for that you will need to make 3 changes to your project:

1. For RAD Studio prior to 11.3, open the source of your Delphi Application Project (.dpr), include the line Application.BiDiMode := TBiDiMode.bdRightToLeft;, like below:

program Project1;

uses
  System.StartUpCopy,
  FMX.Forms,
  System.Classes,
  FMX.Skia,
  Unit1 in 'Unit1.pas' {Form1};

{$R *.res}

begin
  Application.BiDiMode := TBiDiMode.bdRightToLeft;
  GlobalUseSkia := True;
  Application.Initialize;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.

2. Set the property BiDiMode of your forms to bdRightToLeft;
3. Keyboard input controls like TEdit and TMemo, need to be fixed by Embarcadero, meanwhile, as a workaround, set the ControlType property of these controls to Platform.

Custom fonts

Using Skia's renderer, it is possible to use custom font in any FMX control, on any platform in a very simple way. Just register them in the app initialization:

program Project1;

uses
  System.StartUpCopy,
  FMX.Forms,
  FMX.Skia,
  Unit1 in 'Unit1.pas' {Form1};

{$R *.res}

begin
  GlobalUseSkia := True;
  TSkDefaultProviders.RegisterTypeface('Poppins.ttf');
  Application.Initialize;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.

On RAD Studio 12 Athens or newer it is recommended to use IFMXFontManagerService:

program Project1;

uses
  System.StartUpCopy,
  FMX.Forms,
  FMX.Platform,
  FMX.FontManager,
  FMX.Skia,
  Unit1 in 'Unit1.pas' {Form1};

{$R *.res}

begin
  GlobalUseSkia := True;
  var LFontManager: IFMXFontManagerService;
  if TPlatformServices.Current.SupportsPlatformService(IFMXFontManagerService, LFontManager) then
    LFontManager.AddCustomFontFromFile('Poppins.ttf');
  Application.Initialize;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.

Controls VCL/FMX

TSkAnimatedImage

TSkAnimatedImage is the control that can load and render animated images, including vector animations, in a very simple way. The supported formats are:

The example below demonstrates how to play lottie files using TSkAnimatedImage:

  var LAnimatedimage := TSkAnimatedImage.Create(Self);
  LAnimatedimage.LoadFromFile('Samples\Demo\Assets\rocket.json');
  LAnimatedimage.Parent := Self;

The example above results in the output below:

Learn more...

TSkLabel

TSkLabel is the control that implements the SkParagraph internally, having several more features than the TLabel, such as:

• Font families; (font fallback list like in css)
• Font weight;
• Font slant;
• Support for multiple styles in text;
• Support for BiDi; (Right-to-Left)
• Support justify horizontal alignment;
• Support custom font; (without install the font)
• Supports background color on parts of the text;
• Limit the maximum number of lines;
• Auto size option; (width and height)
• Advanced decorations; (like underline wavy, overline, dashed line, among others...) and much more...

Learn more...

TSkPaintBox

TSkPaintBox is the ideal control for painting with Skia API directly on the canvas with the event OnDraw:

procedure TForm1.SkPaintBox1Draw(ASender: TObject; const ACanvas: ISkCanvas;
  const ADest: TRectF; const AOpacity: Single);
begin
  var LPaint: ISkPaint := TSkPaint.Create;
  LPaint.Shader := TSkShader.MakeGradientSweep(ADest.CenterPoint,
    [$FFFCE68D, $FFF7CAA5, $FF2EBBC1, $FFFCE68D]);
  ACanvas.DrawPaint(LPaint);
end;

The example above results in the output below:

Note: The TSkPaintBox has a drawing caching system. To force a drawing refresh, call TSkPaintBox.Redraw. However, this cache system does not exist in FMX apps that have enabled Skia4Delphi render for optimization reasons.

TSkSvg

TSkSvg is the control to load and display SVG easily:

  var LSvg := TSkSvg.Create(Self);
  LSvg.Svg.Source := TFile.ReadAllText('Samples\Demo\Assets\panda.svg');
  LSvg.Parent := Self;

The example above results in the output below:

Learn more...

Compatibility

For the platforms supported by Skia4Delphi (listed above), the OS versions supported by the library are the same OS versions that RAD Studio supports.

Documentation

The APIs are very similar to Skia's, few methods and functions have been renamed for readability, so the Skia documentation can be used.

Version

Skia4Delphi 6.2.0

Skia Version used: chrome/m107

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