DPI/PPI
DPI/PPI (Dots/Pixels Per Inch)
DPI (dots per inch) and PPI (pixels per inch) measure image resolution density. PPI describes screen display density, while DPI refers to print output resolution. 72 PPI is standard for web, 300 DPI for print.
技術的詳細
PPI affects display size: a 3000x2000 pixel image at 300 PPI prints as 10x6.67 inches. Changing PPI metadata without resampling does not alter pixel data or file size.
例
```javascript
// DPI/PPI: 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)
```
関連ツール
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Compress Image
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SVG to PNG
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Pixelate Image
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Strip Image Metadata