Alpha Compositing
Combining semi-transparent images by blending pixel colors according to their alpha channel values.
技术细节
Alpha Compositing determines the level of detail an image can capture. In digital imaging, resolution is typically stated as width x height in pixels (e.g. 3840x2160 for 4K). For print, PPI (pixels per inch) maps these pixels to physical dimensions — 300 PPI is standard for professional printing while 72-96 PPI suffices for screen display. Increasing resolution beyond the original capture requires interpolation algorithms (bicubic, Lanczos) that estimate new pixel values, which adds softness rather than true detail.
示例
```javascript
// Alpha Compositing: processing with Canvas API
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
ctx.drawImage(sourceImage, 0, 0);
const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
// Process pixels in imageData.data (RGBA array)
```
相关工具
相关术语
Metadata
Rasterization
Resolution
DPI
Color Space
Alpha Channel
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)
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
Aspect Ratio
Convolution
Canvas
Compression Artifact
DPI/PPI
Gamma
Histogram