486 lines
14 KiB
JavaScript
486 lines
14 KiB
JavaScript
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/**
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* @author shaozilee
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*
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* Bmp format decoder,support 1bit 4bit 8bit 24bit bmp
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*
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*/
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function BmpDecoder(buffer,is_with_alpha) {
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this.pos = 0;
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this.buffer = buffer;
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this.is_with_alpha = !!is_with_alpha;
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this.bottom_up = true;
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this.flag = this.buffer.toString("utf-8", 0, this.pos += 2);
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if (this.flag != "BM") throw new Error("Invalid BMP File");
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this.parseHeader();
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this.parseRGBA();
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}
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BmpDecoder.prototype.parseHeader = function() {
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this.fileSize = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.reserved = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.offset = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.headerSize = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.width = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.height = this.buffer.readInt32LE(this.pos);
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this.pos += 4;
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this.planes = this.buffer.readUInt16LE(this.pos);
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this.pos += 2;
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this.bitPP = this.buffer.readUInt16LE(this.pos);
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this.pos += 2;
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this.compress = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.rawSize = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.hr = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.vr = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.colors = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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this.importantColors = this.buffer.readUInt32LE(this.pos);
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this.pos += 4;
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if(this.bitPP === 16 && this.is_with_alpha){
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this.bitPP = 15
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}
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if (this.bitPP < 15) {
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var len = this.colors === 0 ? 1 << this.bitPP : this.colors;
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this.palette = new Array(len);
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for (var i = 0; i < len; i++) {
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var blue = this.buffer.readUInt8(this.pos++);
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var green = this.buffer.readUInt8(this.pos++);
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var red = this.buffer.readUInt8(this.pos++);
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var quad = this.buffer.readUInt8(this.pos++);
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this.palette[i] = {
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red: red,
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green: green,
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blue: blue,
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quad: quad
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};
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}
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}
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if(this.height < 0) {
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this.height *= -1;
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this.bottom_up = false;
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}
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}
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BmpDecoder.prototype.parseRGBA = function() {
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var bitn = "bit" + this.bitPP;
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var len = this.width * this.height * 4;
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this.data = new Buffer(len);
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this[bitn]();
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};
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BmpDecoder.prototype.bit1 = function() {
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var xlen = Math.ceil(this.width / 8);
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var mode = xlen%4;
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var y = this.height >= 0 ? this.height - 1 : -this.height
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for (var y = this.height - 1; y >= 0; y--) {
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var line = this.bottom_up ? y : this.height - 1 - y
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for (var x = 0; x < xlen; x++) {
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var b = this.buffer.readUInt8(this.pos++);
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var location = line * this.width * 4 + x*8*4;
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for (var i = 0; i < 8; i++) {
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if(x*8+i<this.width){
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var rgb = this.palette[((b>>(7-i))&0x1)];
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this.data[location+i*4] = 0;
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this.data[location+i*4 + 1] = rgb.blue;
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this.data[location+i*4 + 2] = rgb.green;
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this.data[location+i*4 + 3] = rgb.red;
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}else{
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break;
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}
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}
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}
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if (mode != 0){
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this.pos+=(4 - mode);
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}
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}
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};
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BmpDecoder.prototype.bit4 = function() {
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//RLE-4
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if(this.compress == 2){
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this.data.fill(0xff);
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var location = 0;
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var lines = this.bottom_up?this.height-1:0;
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var low_nibble = false;//for all count of pixel
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while(location<this.data.length){
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var a = this.buffer.readUInt8(this.pos++);
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var b = this.buffer.readUInt8(this.pos++);
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//absolute mode
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if(a == 0){
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if(b == 0){//line end
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if(this.bottom_up){
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lines--;
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}else{
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lines++;
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}
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location = lines*this.width*4;
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low_nibble = false;
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continue;
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}else if(b == 1){//image end
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break;
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}else if(b ==2){
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//offset x,y
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var x = this.buffer.readUInt8(this.pos++);
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var y = this.buffer.readUInt8(this.pos++);
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if(this.bottom_up){
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lines-=y;
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}else{
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lines+=y;
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}
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location +=(y*this.width*4+x*4);
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}else{
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var c = this.buffer.readUInt8(this.pos++);
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for(var i=0;i<b;i++){
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if (low_nibble) {
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setPixelData.call(this, (c & 0x0f));
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} else {
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setPixelData.call(this, (c & 0xf0)>>4);
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}
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if ((i & 1) && (i+1 < b)){
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c = this.buffer.readUInt8(this.pos++);
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}
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low_nibble = !low_nibble;
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}
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if ((((b+1) >> 1) & 1 ) == 1){
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this.pos++
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}
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}
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}else{//encoded mode
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for (var i = 0; i < a; i++) {
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if (low_nibble) {
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setPixelData.call(this, (b & 0x0f));
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} else {
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setPixelData.call(this, (b & 0xf0)>>4);
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}
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low_nibble = !low_nibble;
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}
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}
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}
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function setPixelData(rgbIndex){
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var rgb = this.palette[rgbIndex];
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this.data[location] = 0;
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this.data[location + 1] = rgb.blue;
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this.data[location + 2] = rgb.green;
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this.data[location + 3] = rgb.red;
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location+=4;
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}
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}else{
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var xlen = Math.ceil(this.width/2);
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var mode = xlen%4;
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for (var y = this.height - 1; y >= 0; y--) {
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var line = this.bottom_up ? y : this.height - 1 - y
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for (var x = 0; x < xlen; x++) {
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var b = this.buffer.readUInt8(this.pos++);
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var location = line * this.width * 4 + x*2*4;
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var before = b>>4;
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var after = b&0x0F;
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var rgb = this.palette[before];
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this.data[location] = 0;
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this.data[location + 1] = rgb.blue;
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this.data[location + 2] = rgb.green;
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this.data[location + 3] = rgb.red;
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if(x*2+1>=this.width)break;
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rgb = this.palette[after];
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this.data[location+4] = 0;
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this.data[location+4 + 1] = rgb.blue;
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this.data[location+4 + 2] = rgb.green;
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this.data[location+4 + 3] = rgb.red;
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}
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if (mode != 0){
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this.pos+=(4 - mode);
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}
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}
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}
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};
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BmpDecoder.prototype.bit8 = function() {
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//RLE-8
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if(this.compress == 1){
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this.data.fill(0xff);
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var location = 0;
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var lines = this.bottom_up?this.height-1:0;
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while(location<this.data.length){
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var a = this.buffer.readUInt8(this.pos++);
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var b = this.buffer.readUInt8(this.pos++);
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//absolute mode
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if(a == 0){
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if(b == 0){//line end
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if(this.bottom_up){
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lines--;
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}else{
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lines++;
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}
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location = lines*this.width*4;
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continue;
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}else if(b == 1){//image end
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break;
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}else if(b ==2){
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//offset x,y
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var x = this.buffer.readUInt8(this.pos++);
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var y = this.buffer.readUInt8(this.pos++);
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if(this.bottom_up){
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lines-=y;
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}else{
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lines+=y;
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}
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location +=(y*this.width*4+x*4);
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}else{
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for(var i=0;i<b;i++){
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var c = this.buffer.readUInt8(this.pos++);
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setPixelData.call(this, c);
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}
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if(b&1 == 1){
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this.pos++;
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}
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}
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}else{//encoded mode
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for (var i = 0; i < a; i++) {
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setPixelData.call(this, b);
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}
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}
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}
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function setPixelData(rgbIndex){
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var rgb = this.palette[rgbIndex];
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this.data[location] = 0;
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this.data[location + 1] = rgb.blue;
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this.data[location + 2] = rgb.green;
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this.data[location + 3] = rgb.red;
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location+=4;
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}
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}else {
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var mode = this.width % 4;
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for (var y = this.height - 1; y >= 0; y--) {
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var line = this.bottom_up ? y : this.height - 1 - y
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for (var x = 0; x < this.width; x++) {
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var b = this.buffer.readUInt8(this.pos++);
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var location = line * this.width * 4 + x * 4;
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if (b < this.palette.length) {
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var rgb = this.palette[b];
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this.data[location] = 0;
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this.data[location + 1] = rgb.blue;
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this.data[location + 2] = rgb.green;
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this.data[location + 3] = rgb.red;
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} else {
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this.data[location] = 0;
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this.data[location + 1] = 0xFF;
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this.data[location + 2] = 0xFF;
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this.data[location + 3] = 0xFF;
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}
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}
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if (mode != 0) {
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this.pos += (4 - mode);
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}
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}
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}
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};
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BmpDecoder.prototype.bit15 = function() {
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var dif_w =this.width % 3;
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var _11111 = parseInt("11111", 2),_1_5 = _11111;
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for (var y = this.height - 1; y >= 0; y--) {
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var line = this.bottom_up ? y : this.height - 1 - y
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for (var x = 0; x < this.width; x++) {
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var B = this.buffer.readUInt16LE(this.pos);
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this.pos+=2;
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var blue = (B & _1_5) / _1_5 * 255 | 0;
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var green = (B >> 5 & _1_5 ) / _1_5 * 255 | 0;
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var red = (B >> 10 & _1_5) / _1_5 * 255 | 0;
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var alpha = (B>>15)?0xFF:0x00;
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var location = line * this.width * 4 + x * 4;
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this.data[location] = alpha;
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this.data[location + 1] = blue;
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this.data[location + 2] = green;
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this.data[location + 3] = red;
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}
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//skip extra bytes
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this.pos += dif_w;
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}
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};
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BmpDecoder.prototype.bit16 = function() {
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var dif_w =(this.width % 2)*2;
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//default xrgb555
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this.maskRed = 0x7C00;
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this.maskGreen = 0x3E0;
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this.maskBlue =0x1F;
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this.mask0 = 0;
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if(this.compress == 3){
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this.maskRed = this.buffer.readUInt32LE(this.pos);
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this.pos+=4;
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this.maskGreen = this.buffer.readUInt32LE(this.pos);
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this.pos+=4;
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this.maskBlue = this.buffer.readUInt32LE(this.pos);
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this.pos+=4;
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this.mask0 = this.buffer.readUInt32LE(this.pos);
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this.pos+=4;
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}
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var ns=[0,0,0];
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for (var i=0;i<16;i++){
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if ((this.maskRed>>i)&0x01) ns[0]++;
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if ((this.maskGreen>>i)&0x01) ns[1]++;
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if ((this.maskBlue>>i)&0x01) ns[2]++;
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}
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|
|
ns[1]+=ns[0]; ns[2]+=ns[1]; ns[0]=8-ns[0]; ns[1]-=8; ns[2]-=8;
|
||
|
|
|
||
|
|
for (var y = this.height - 1; y >= 0; y--) {
|
||
|
|
var line = this.bottom_up ? y : this.height - 1 - y;
|
||
|
|
for (var x = 0; x < this.width; x++) {
|
||
|
|
|
||
|
|
var B = this.buffer.readUInt16LE(this.pos);
|
||
|
|
this.pos+=2;
|
||
|
|
|
||
|
|
var blue = (B&this.maskBlue)<<ns[0];
|
||
|
|
var green = (B&this.maskGreen)>>ns[1];
|
||
|
|
var red = (B&this.maskRed)>>ns[2];
|
||
|
|
|
||
|
|
var location = line * this.width * 4 + x * 4;
|
||
|
|
|
||
|
|
this.data[location] = 0;
|
||
|
|
this.data[location + 1] = blue;
|
||
|
|
this.data[location + 2] = green;
|
||
|
|
this.data[location + 3] = red;
|
||
|
|
}
|
||
|
|
//skip extra bytes
|
||
|
|
this.pos += dif_w;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
BmpDecoder.prototype.bit24 = function() {
|
||
|
|
for (var y = this.height - 1; y >= 0; y--) {
|
||
|
|
var line = this.bottom_up ? y : this.height - 1 - y
|
||
|
|
for (var x = 0; x < this.width; x++) {
|
||
|
|
//Little Endian rgb
|
||
|
|
var blue = this.buffer.readUInt8(this.pos++);
|
||
|
|
var green = this.buffer.readUInt8(this.pos++);
|
||
|
|
var red = this.buffer.readUInt8(this.pos++);
|
||
|
|
var location = line * this.width * 4 + x * 4;
|
||
|
|
this.data[location] = 0;
|
||
|
|
this.data[location + 1] = blue;
|
||
|
|
this.data[location + 2] = green;
|
||
|
|
this.data[location + 3] = red;
|
||
|
|
}
|
||
|
|
//skip extra bytes
|
||
|
|
this.pos += (this.width % 4);
|
||
|
|
}
|
||
|
|
|
||
|
|
};
|
||
|
|
|
||
|
|
/**
|
||
|
|
* add 32bit decode func
|
||
|
|
* @author soubok
|
||
|
|
*/
|
||
|
|
BmpDecoder.prototype.bit32 = function() {
|
||
|
|
//BI_BITFIELDS
|
||
|
|
if(this.compress == 3){
|
||
|
|
this.maskRed = this.buffer.readUInt32LE(this.pos);
|
||
|
|
this.pos+=4;
|
||
|
|
this.maskGreen = this.buffer.readUInt32LE(this.pos);
|
||
|
|
this.pos+=4;
|
||
|
|
this.maskBlue = this.buffer.readUInt32LE(this.pos);
|
||
|
|
this.pos+=4;
|
||
|
|
this.mask0 = this.buffer.readUInt32LE(this.pos);
|
||
|
|
this.pos+=4;
|
||
|
|
for (var y = this.height - 1; y >= 0; y--) {
|
||
|
|
var line = this.bottom_up ? y : this.height - 1 - y;
|
||
|
|
for (var x = 0; x < this.width; x++) {
|
||
|
|
//Little Endian rgba
|
||
|
|
var alpha = this.buffer.readUInt8(this.pos++);
|
||
|
|
var blue = this.buffer.readUInt8(this.pos++);
|
||
|
|
var green = this.buffer.readUInt8(this.pos++);
|
||
|
|
var red = this.buffer.readUInt8(this.pos++);
|
||
|
|
var location = line * this.width * 4 + x * 4;
|
||
|
|
this.data[location] = alpha;
|
||
|
|
this.data[location + 1] = blue;
|
||
|
|
this.data[location + 2] = green;
|
||
|
|
this.data[location + 3] = red;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
}else{
|
||
|
|
for (var y = this.height - 1; y >= 0; y--) {
|
||
|
|
var line = this.bottom_up ? y : this.height - 1 - y;
|
||
|
|
for (var x = 0; x < this.width; x++) {
|
||
|
|
//Little Endian argb
|
||
|
|
var blue = this.buffer.readUInt8(this.pos++);
|
||
|
|
var green = this.buffer.readUInt8(this.pos++);
|
||
|
|
var red = this.buffer.readUInt8(this.pos++);
|
||
|
|
var alpha = this.buffer.readUInt8(this.pos++);
|
||
|
|
var location = line * this.width * 4 + x * 4;
|
||
|
|
this.data[location] = alpha;
|
||
|
|
this.data[location + 1] = blue;
|
||
|
|
this.data[location + 2] = green;
|
||
|
|
this.data[location + 3] = red;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
};
|
||
|
|
|
||
|
|
BmpDecoder.prototype.getData = function() {
|
||
|
|
return this.data;
|
||
|
|
};
|
||
|
|
|
||
|
|
module.exports = function(bmpData) {
|
||
|
|
var decoder = new BmpDecoder(bmpData);
|
||
|
|
return decoder;
|
||
|
|
};
|