refactor: rename bitDepth to depth

BREAKING CHANGE:

The `bitDepth` field was renamed to `depth`.

Author: targos

README.md

@@ -32,7 +32,7 @@ PNG image decoder and encoder written entirely in JavaScript.
   - `width` - The width of the image
   - `height` - The height of the image
   - `data` - An array or TypedArray with the image data
-  - `bitDepth` - A number indicating the bit depth (only 8 and 16 are supported now). Defaults to 8.
+  - `depth` - A number indicating the color depth (only 8 and 16 are supported now). Defaults to 8.
   - `components` - Number of non-alpha channels (1 or 3 are supported). Defaults to 3.
   - `alpha` - Boolean indicating if an alpha channel is present. Defaults to true.
 

src/PNGDecoder.ts

@@ -114,7 +114,7 @@ export default class PNGDecoder extends IOBuffer {
     const image = this._png;
     image.width = this.readUint32();
     image.height = this.readUint32();
-    image.bitDepth = this.readUint8();
+    image.depth = this.readUint8();
     image.colourType = this.readUint8();
     image.compressionMethod = this.readUint8();
     image.filterMethod = this.readUint8();
@@ -216,7 +216,7 @@ export default class PNGDecoder extends IOBuffer {
     }
 
     const height = this._png.height;
-    const bytesPerPixel = (channels * this._png.bitDepth) / 8;
+    const bytesPerPixel = (channels * this._png.depth) / 8;
     const bytesPerLine = this._png.width * bytesPerPixel;
     const newData = new Uint8Array(this._png.height * bytesPerLine);
 
@@ -267,7 +267,7 @@ export default class PNGDecoder extends IOBuffer {
       this._png.palette = this._palette;
     }
 
-    if (this._png.bitDepth === 16) {
+    if (this._png.depth === 16) {
       const uint16Data = new Uint16Array(newData.buffer);
       if (osIsLittleEndian) {
         for (let k = 0; k < uint16Data.length; k++) {

src/PNGEncoder.ts

@@ -48,7 +48,7 @@ export default class PNGEncoder extends IOBuffer {
 
     this.writeUint32(this._png.width);
     this.writeUint32(this._png.height);
-    this.writeByte(this._png.bitDepth);
+    this.writeByte(this._png.depth);
     this.writeByte(this._png.colourType);
     this.writeByte(0); // Compression method
     this.writeByte(0); // Filter method
@@ -78,16 +78,16 @@ export default class PNGEncoder extends IOBuffer {
   }
 
   private encodeData(): void {
-    const { width, height, channels, bitDepth, data } = this._png;
+    const { width, height, channels, depth, data } = this._png;
     const slotsPerLine = channels * width;
     const newData = new IOBuffer().setBigEndian();
     let offset = 0;
     for (let i = 0; i < height; i++) {
       newData.writeByte(0); // no filter
       /* istanbul ignore else */
-      if (bitDepth === 8) {
+      if (depth === 8) {
         offset = writeDataBytes(data, newData, slotsPerLine, offset);
-      } else if (bitDepth === 16) {
+      } else if (depth === 16) {
         offset = writeDataUint16(data, newData, slotsPerLine, offset);
       } else {
         throw new Error('unreachable');
@@ -102,10 +102,10 @@ export default class PNGEncoder extends IOBuffer {
     this._png.width = checkInteger(data.width, 'width');
     this._png.height = checkInteger(data.height, 'height');
     this._png.data = data.data;
-    const { colourType, channels, bitDepth } = getColourType(data);
+    const { colourType, channels, depth } = getColourType(data);
     this._png.colourType = colourType;
     this._png.channels = channels;
-    this._png.bitDepth = bitDepth;
+    this._png.depth = depth;
     const expectedSize = this._png.width * this._png.height * channels;
     if (this._png.data.length !== expectedSize) {
       throw new RangeError(
@@ -139,13 +139,13 @@ function checkInteger(value: number, name: string): number {
 
 function getColourType(
   data: IImageData
-): { channels: number; bitDepth: number; colourType: number } {
-  let { components = 3, bitDepth = 8 } = data;
+): { channels: number; depth: number; colourType: number } {
+  let { components = 3, depth = 8 } = data;
   if (components !== 3 && components !== 1) {
     throw new RangeError(`unsupported number of components: ${components}`);
   }
-  if (bitDepth !== 8 && bitDepth !== 16) {
-    throw new RangeError(`unsupported bit depth: ${bitDepth}`);
+  if (depth !== 8 && depth !== 16) {
+    throw new RangeError(`unsupported bit depth: ${depth}`);
   }
 
   let { alpha = true } = data;
@@ -157,7 +157,7 @@ function getColourType(
   }
 
   const channels = components + Number(alpha);
-  const returnValue = { channels, bitDepth, colourType: -1 };
+  const returnValue = { channels, depth, colourType: -1 };
   switch (channels) {
     case 4:
       returnValue.colourType = 6;

src/__tests__/decode.test.ts

@@ -11,7 +11,7 @@ describe('decode', () => {
     check(img, {
       width: 2,
       height: 2,
-      bitDepth: 8,
+      depth: 8,
       colourType: 4
     });
     expect(img.data).toBeInstanceOf(Uint8Array);
@@ -25,7 +25,7 @@ describe('decode', () => {
     check(img, {
       width: 10,
       height: 10,
-      bitDepth: 8,
+      depth: 8,
       colourType: 6
     });
     expect(img.data).toBeInstanceOf(Uint8Array);
@@ -37,7 +37,7 @@ describe('decode', () => {
     check(img, {
       width: 150,
       height: 200,
-      bitDepth: 8,
+      depth: 8,
       colourType: 3
     });
     expect(img.palette).toBeInstanceOf(Array);

src/__tests__/encode.test.ts

@@ -33,7 +33,7 @@ describe('encode', () => {
     const expected = {
       width: 2,
       height: 2,
-      bitDepth: 8,
+      depth: 8,
       colourType: 6
     };
     check(decoded, expected);
@@ -56,7 +56,7 @@ describe('encode', () => {
     const expected = {
       width: 2,
       height: 3,
-      bitDepth: 8,
+      depth: 8,
       colourType: 0
     };
     check(decoded, expected);
@@ -83,7 +83,7 @@ describe('encode', () => {
     const data = encode({
       width: 2,
       height: 2,
-      bitDepth: 16,
+      depth: 16,
       data: dataArray,
       components: 3,
       alpha: false
@@ -93,7 +93,7 @@ describe('encode', () => {
     const expected = {
       width: 2,
       height: 2,
-      bitDepth: 16,
+      depth: 16,
       colourType: 2
     };
     check(decoded, expected);
@@ -129,7 +129,7 @@ describe('encode', () => {
     const expected = {
       width: 2,
       height: 3,
-      bitDepth: 8,
+      depth: 8,
       colourType: 4
     };
     check(decoded, expected);
@@ -143,7 +143,7 @@ describe('encode', () => {
       encode({
         width: 1,
         height: 1,
-        bitDepth: 8,
+        depth: 8,
         data: new Uint8Array(),
         components: 5,
         alpha: true
@@ -153,7 +153,7 @@ describe('encode', () => {
       encode({
         width: 1,
         height: 1,
-        bitDepth: 8,
+        depth: 8,
         data: new Uint8Array(),
         components: 3,
         // @ts-ignore
@@ -164,7 +164,7 @@ describe('encode', () => {
       encode({
         width: 1.1,
         height: 1,
-        bitDepth: 8,
+        depth: 8,
         data: new Uint8Array(),
         components: 3,
         alpha: false
@@ -175,7 +175,7 @@ describe('encode', () => {
         width: 1,
         // @ts-ignore
         height: undefined,
-        bitDepth: 8,
+        depth: 8,
         data: new Uint8Array(),
         components: 3,
         alpha: false
@@ -185,7 +185,7 @@ describe('encode', () => {
       encode({
         width: 1,
         height: 1,
-        bitDepth: 8,
+        depth: 8,
         data: new Uint8Array(10),
         components: 3,
         alpha: false
@@ -195,7 +195,7 @@ describe('encode', () => {
       encode({
         width: 1,
         height: 1,
-        bitDepth: 1,
+        depth: 1,
         data: new Uint8Array(10),
         components: 3,
         alpha: false
@@ -215,10 +215,6 @@ function check(img: any, values: any): void {
 function checkPngJs(data: any, values: any): void {
   const img = PNG.sync.read(Buffer.from(data, data.byteOffset, data.length));
   var newValues = Object.assign({}, values);
-  if (newValues.bitDepth !== undefined) {
-    newValues.depth = newValues.bitDepth;
-    delete newValues.bitDepth;
-  }
   if (newValues.colourType !== undefined) {
     newValues.colorType = newValues.colourType;
     delete newValues.colourType;

src/types.ts

@@ -8,10 +8,10 @@ export type PNGDataArray = Uint8Array | Uint16Array;
 export type DecoderInputType = IOBuffer | ArrayBufferLike | ArrayBufferView;
 
 export interface IDecodedPNG {
-  height: number;
   width: number;
+  height: number;
   data: PNGDataArray;
-  bitDepth: number;
+  depth: number;
   colourType: number;
   channels: number;
   compressionMethod: number;
@@ -31,9 +31,9 @@ export interface IImageData {
   width: number;
   height: number;
   data: PNGDataArray;
+  depth?: number;
   components?: number;
   alpha?: boolean | 0 | 1;
-  bitDepth?: number;
 }
 
 export interface IPNGEncoderOptions {