Palette

The Palette APIs support in selecting colors from images to help you create visually engaging apps.

You can use the Palette APIs to design layout themes and apply custom colors to visual elements in your application. For example, you can use a Palette to create a color-coordinated title card for a song based on its album cover, or to adjust an app’s toolbar color when its background image changes. The Palette object gives you access to the colors in a bitmap image, while also providing six main color profiles from the bitmap to help your design choices.

Add namespace

To implement Palette, include Tizen.NUI namespace in your application:

                
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using Tizen.NUI;

Create Palette

Generate a Palette instance using the ImageLoading to first create a PixelBuffer from an image.

1. Create PixelBuffer from source image:

   
                   
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   PixelBuffer imgBitmap = ImageLoading.LoadImageFromFile(imagePath);   
   

   • You can generate the Palette either synchronously or asynchronously.

2. Generate a Palette synchronously or asynchronously:

   
                   
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   // Generate a Palette synchronously
   public void PaletteGeneratesync()
   {
       PixelBuffer imgBitmap = ImageLoading.LoadImageFromFile(_imgPath);
       try
       {
           Palette palette = Palette.Generate(imgBitmap);
       }
       catch (ArgumentNullException e)
       {
           //Exception Handling.
       }
   }
   
   // Generate a Palette asynchronously
   public async Task PaletteGenerateAsync()
   {
       PixelBuffer imgBitmap = ImageLoading.LoadImageFromFile(_imgPath);
       try
       {
           Palette palette = await Palette.GenerateAsync(imgBitmap);
       }
       catch (ArgumentNullException e)
       {
           //Exception Handling.
       }
   }
   

3. Set a region of the PixelBuffer to be used exclusively when calculating the Palette. This is optional:

   
                   
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   Rectangle rect = new Rectangle(0, 0, 100, 100);
   ...
   Palette palette = Palette.Generate(imgBitmap, rect);
   

Extract color profiles

Colors extracted from the bitmap image are scored against each profile based on saturation, luminance, and population (number of pixels in the bitmap represented by the color). For each profile, the color with the best score defines that color profile for the given image. Palette object contains 16 primary colors from a given image.

The Palette library attempts to extract the following six color profiles:

• Light vibrant
• Vibrant
• Dark vibrant
• Light muted
• Muted
• Dark muted

Each of the Palettes get<Profile>Color() returns the color in the Palette associated with that particular profile, where is replaced by the name of one of the six color profiles. For example, the method to get the Dark Vibrant color profile is getDarkVibrantColor(). Not all images contain all color profiles, you must also provide a default color to return:

To access all colors in a Palette, the getSwatches() returns a list of all swatches generated from an image, including the standard six color profiles.

Use swatches to create color schemes

The Palette class also generates Palette.Swatch objects for each color profile. The Palette.Swatch objects contain the associated color for that profile as well as the population of colors in pixels. Swatches have additional methods for accessing more information about the color profile, such as HSL values and pixel population. You can use swatches to create more comprehensive color schemes and app themes using the getBodyTextColor() and getTitleTextColor().

The following methods return colors that are appropriate for use over the swatch’s color:

• Each of Palettes get<Profile>Swatch() returns the swatch associated with that particular profile, where is replaced by the name of one of the six color profiles.

• The Palettes get<Profile>Swatch() does not require default value parameters, the method returns null if a particular profile does not exist in the image. Therefore, you must ensure that a swatch is not null before using it. For example, the following code gets the title text color from a Palette, if the vibrant swatch is not null:

  
                  
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  var mutedSwatch = palette.GetMutedSwatch();
  TextLabel label = new TextLabel(txt)
  {
      TextColor = mutedSwatch.GetBodyTextColor(),
      ...
  };
  

Related information

• Dependencies
  • Tizen 6.5 and Higher