What is Alpha Channel?

Alpha Channel — Image Transparency Explained

An alpha channel stores transparency information for each pixel in an image, with values ranging from fully transparent to fully opaque. It is the fourth channel in RGBA color, enabling smooth blending of images over backgrounds.

Detalhe técnico

Alpha values are typically stored as 8-bit (0-255) or floating point (0.0-1.0) per pixel. Pre-multiplied alpha multiplies color values by opacity for faster compositing, while straight alpha stores them independently.

Exemplo

```javascript
// Convert RGB to HSL
function rgbToHsl(r, g, b) {
  r /= 255; g /= 255; b /= 255;
  const max = Math.max(r, g, b), min = Math.min(r, g, b);
  const l = (max + min) / 2;
  let h = 0, s = 0;
  if (max !== min) {
    const d = max - min;
    s = l > 0.5 ? d/(2-max-min) : d/(max+min);
  }
  return [h, s, l];
}
```

Ferramentas relacionadas

C Comprimir Imagem R Redimensionar Imagem R Recortar Imagem G Girar Imagem E Espelhar Imagem C Converter Imagem M Marca d'Água em Imagem S SVG para PNG I Imagem para Base64 A Arredondar Cantos A Adicionar Borda F Filtros de Imagem A Ajustar Imagem D Desfocar Imagem N Nitidez de Imagem T Tornar Quadrada G Grayscale Image S Sepia Image P Pixelate Image S Strip Image Metadata

Termos relacionados

Metadata Rasterization Resolution DPI Color Space Lossy Compression Lossless Compression EXIF Color Profile Bit Depth Vector Graphics Raster Graphics Chroma Subsampling HDR WebP AVIF Sprite Sheet Thumbnail Crop Resize Image Optimization Image Histogram Noise Reduction (Image) Panorama Stitching Image Segmentation Object Detection Feature Matching Image Interpolation Dithering (Image) Alpha Compositing Image Pyramid Mipmap Texture Atlas Image Registration Morphological Operations IPTC ICC Profile Gamut Mapping Tone Mapping Chromatic Aberration Vignetting XMP Color Grading (Image) Focus Stacking Content-Aware Fill Batch Resize Channel Aspect Ratio Convolution Canvas Compression Artifact DPI/PPI Gamma Histogram