|
|
@@ -0,0 +1,148 @@
|
|
|
+import { PNG } from 'pngjs';
|
|
|
+import jpeg from 'jpeg-js';
|
|
|
+import * as fs from 'fs/promises';
|
|
|
+
|
|
|
+class Image {
|
|
|
+
|
|
|
+ constructor( width, height, data ) {
|
|
|
+
|
|
|
+ this.width = width;
|
|
|
+ this.height = height;
|
|
|
+ this.data = data;
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ get bitmap() {
|
|
|
+
|
|
|
+ return { width: this.width, height: this.height, data: this.data };
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ clone() {
|
|
|
+
|
|
|
+ return new Image( this.width, this.height, Buffer.from( this.data ) );
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ scale( factor ) {
|
|
|
+
|
|
|
+ if ( factor >= 1 ) {
|
|
|
+
|
|
|
+ console.warn( 'Image.scale() is optimized for downscaling only.' );
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ const newWidth = Math.round( this.width * factor );
|
|
|
+ const newHeight = Math.round( this.height * factor );
|
|
|
+ const newData = Buffer.alloc( newWidth * newHeight * 4 );
|
|
|
+
|
|
|
+ // Box filter for downscaling (averages all source pixels in the region)
|
|
|
+ const scaleX = this.width / newWidth;
|
|
|
+ const scaleY = this.height / newHeight;
|
|
|
+
|
|
|
+ for ( let y = 0; y < newHeight; y ++ ) {
|
|
|
+
|
|
|
+ for ( let x = 0; x < newWidth; x ++ ) {
|
|
|
+
|
|
|
+ // Calculate source region
|
|
|
+ const srcX0 = x * scaleX;
|
|
|
+ const srcY0 = y * scaleY;
|
|
|
+ const srcX1 = ( x + 1 ) * scaleX;
|
|
|
+ const srcY1 = ( y + 1 ) * scaleY;
|
|
|
+
|
|
|
+ const x0 = Math.floor( srcX0 );
|
|
|
+ const y0 = Math.floor( srcY0 );
|
|
|
+ const x1 = Math.min( Math.ceil( srcX1 ), this.width );
|
|
|
+ const y1 = Math.min( Math.ceil( srcY1 ), this.height );
|
|
|
+
|
|
|
+ const dstIdx = ( y * newWidth + x ) * 4;
|
|
|
+ const sums = [ 0, 0, 0, 0 ];
|
|
|
+ let totalWeight = 0;
|
|
|
+
|
|
|
+ // Average all pixels in the source region with proper weighting
|
|
|
+ for ( let sy = y0; sy < y1; sy ++ ) {
|
|
|
+
|
|
|
+ for ( let sx = x0; sx < x1; sx ++ ) {
|
|
|
+
|
|
|
+ // Calculate coverage weight for edge pixels
|
|
|
+ const wx0 = Math.max( 0, Math.min( 1, sx + 1 - srcX0 ) );
|
|
|
+ const wx1 = Math.max( 0, Math.min( 1, srcX1 - sx ) );
|
|
|
+ const wy0 = Math.max( 0, Math.min( 1, sy + 1 - srcY0 ) );
|
|
|
+ const wy1 = Math.max( 0, Math.min( 1, srcY1 - sy ) );
|
|
|
+ const weight = Math.min( wx0, wx1 ) * Math.min( wy0, wy1 );
|
|
|
+
|
|
|
+ const srcIdx = ( sy * this.width + sx ) * 4;
|
|
|
+ for ( let c = 0; c < 4; c ++ ) {
|
|
|
+
|
|
|
+ sums[ c ] += this.data[ srcIdx + c ] * weight;
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ totalWeight += weight;
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ for ( let c = 0; c < 4; c ++ ) {
|
|
|
+
|
|
|
+ newData[ dstIdx + c ] = Math.round( sums[ c ] / totalWeight );
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ this.width = newWidth;
|
|
|
+ this.height = newHeight;
|
|
|
+ this.data = newData;
|
|
|
+
|
|
|
+ return this;
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ async write( filepath, quality = 95 ) {
|
|
|
+
|
|
|
+ const rawImageData = {
|
|
|
+ data: this.data,
|
|
|
+ width: this.width,
|
|
|
+ height: this.height
|
|
|
+ };
|
|
|
+
|
|
|
+ const encoded = jpeg.encode( rawImageData, quality );
|
|
|
+ await fs.writeFile( filepath, encoded.data );
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ static async read( input ) {
|
|
|
+
|
|
|
+ let buffer;
|
|
|
+
|
|
|
+ if ( typeof input === 'string' ) {
|
|
|
+
|
|
|
+ buffer = await fs.readFile( input );
|
|
|
+
|
|
|
+ } else {
|
|
|
+
|
|
|
+ buffer = input;
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ // Check if PNG (starts with PNG signature)
|
|
|
+ if ( buffer[ 0 ] === 0x89 && buffer[ 1 ] === 0x50 && buffer[ 2 ] === 0x4E && buffer[ 3 ] === 0x47 ) {
|
|
|
+
|
|
|
+ const png = PNG.sync.read( buffer );
|
|
|
+ return new Image( png.width, png.height, png.data );
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+ // Otherwise assume JPEG
|
|
|
+ const decoded = jpeg.decode( buffer, { useTArray: true } );
|
|
|
+ return new Image( decoded.width, decoded.height, Buffer.from( decoded.data ) );
|
|
|
+
|
|
|
+ }
|
|
|
+
|
|
|
+}
|
|
|
+
|
|
|
+export { Image };
|
mrdoob