51 lines
1.2 KiB
TypeScript
51 lines
1.2 KiB
TypeScript
import type { PixelImage } from './types';
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export type ImageInfo = {
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width: number;
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height: number;
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hasAlpha: boolean;
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colorCount: number;
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};
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export function imageInfo(img: PixelImage): ImageInfo {
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let hasAlpha = false;
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const seen = new Set<number>();
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for (let i = 0; i < img.data.length; i += 4) {
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if (!hasAlpha && img.data[i + 3] !== 255) {
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hasAlpha = true;
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}
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const key =
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((img.data[i] << 24) |
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(img.data[i + 1] << 16) |
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(img.data[i + 2] << 8) |
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img.data[i + 3]) >>>
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0;
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seen.add(key);
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}
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return { width: img.width, height: img.height, hasAlpha, colorCount: seen.size };
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}
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export function isGrayscale(img: PixelImage): boolean {
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for (let i = 0; i < img.data.length; i += 4) {
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if (img.data[i] !== img.data[i + 1] || img.data[i + 1] !== img.data[i + 2]) {
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return false;
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}
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}
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return true;
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}
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export function hasTransparency(img: PixelImage): boolean {
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for (let i = 3; i < img.data.length; i += 4) {
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if (img.data[i] < 255) return true;
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}
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return false;
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}
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export type Orientation = 'portrait' | 'landscape' | 'square';
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export function orientationOf(img: PixelImage): Orientation {
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if (img.height > img.width) return 'portrait';
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if (img.width > img.height) return 'landscape';
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return 'square';
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}
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