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Your IP : 3.141.18.167
/**
* @author shaozilee
*
* Bmp format decoder,support 1bit 4bit 8bit 24bit bmp
*
*/
function BmpDecoder(buffer,is_with_alpha) {
this.pos = 0;
this.buffer = buffer;
this.is_with_alpha = !!is_with_alpha;
this.bottom_up = true;
this.flag = this.buffer.toString("utf-8", 0, this.pos += 2);
if (this.flag != "BM") throw new Error("Invalid BMP File");
this.parseHeader();
this.parseRGBA();
}
BmpDecoder.prototype.parseHeader = function() {
this.fileSize = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.reserved = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.offset = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.headerSize = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.width = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.height = this.buffer.readInt32LE(this.pos);
this.pos += 4;
this.planes = this.buffer.readUInt16LE(this.pos);
this.pos += 2;
this.bitPP = this.buffer.readUInt16LE(this.pos);
this.pos += 2;
this.compress = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.rawSize = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.hr = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.vr = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.colors = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
this.importantColors = this.buffer.readUInt32LE(this.pos);
this.pos += 4;
if(this.bitPP === 16 && this.is_with_alpha){
this.bitPP = 15
}
if (this.bitPP < 15) {
var len = this.colors === 0 ? 1 << this.bitPP : this.colors;
this.palette = new Array(len);
for (var i = 0; i < len; i++) {
var blue = this.buffer.readUInt8(this.pos++);
var green = this.buffer.readUInt8(this.pos++);
var red = this.buffer.readUInt8(this.pos++);
var quad = this.buffer.readUInt8(this.pos++);
this.palette[i] = {
red: red,
green: green,
blue: blue,
quad: quad
};
}
}
if(this.height < 0) {
this.height *= -1;
this.bottom_up = false;
}
}
BmpDecoder.prototype.parseRGBA = function() {
var bitn = "bit" + this.bitPP;
var len = this.width * this.height * 4;
this.data = new Buffer(len);
this[bitn]();
};
BmpDecoder.prototype.bit1 = function() {
var xlen = Math.ceil(this.width / 8);
var mode = xlen%4;
var y = this.height >= 0 ? this.height - 1 : -this.height
for (var y = this.height - 1; y >= 0; y--) {
var line = this.bottom_up ? y : this.height - 1 - y
for (var x = 0; x < xlen; x++) {
var b = this.buffer.readUInt8(this.pos++);
var location = line * this.width * 4 + x*8*4;
for (var i = 0; i < 8; i++) {
if(x*8+i<this.width){
var rgb = this.palette[((b>>(7-i))&0x1)];
this.data[location+i*4] = 0;
this.data[location+i*4 + 1] = rgb.blue;
this.data[location+i*4 + 2] = rgb.green;
this.data[location+i*4 + 3] = rgb.red;
}else{
break;
}
}
}
if (mode != 0){
this.pos+=(4 - mode);
}
}
};
BmpDecoder.prototype.bit4 = function() {
//RLE-4
if(this.compress == 2){
this.data.fill(0xff);
var location = 0;
var lines = this.bottom_up?this.height-1:0;
var low_nibble = false;//for all count of pixel
while(location<this.data.length){
var a = this.buffer.readUInt8(this.pos++);
var b = this.buffer.readUInt8(this.pos++);
//absolute mode
if(a == 0){
if(b == 0){//line end
if(this.bottom_up){
lines--;
}else{
lines++;
}
location = lines*this.width*4;
low_nibble = false;
continue;
}else if(b == 1){//image end
break;
}else if(b ==2){
//offset x,y
var x = this.buffer.readUInt8(this.pos++);
var y = this.buffer.readUInt8(this.pos++);
if(this.bottom_up){
lines-=y;
}else{
lines+=y;
}
location +=(y*this.width*4+x*4);
}else{
var c = this.buffer.readUInt8(this.pos++);
for(var i=0;i<b;i++){
if (low_nibble) {
setPixelData.call(this, (c & 0x0f));
} else {
setPixelData.call(this, (c & 0xf0)>>4);
}
if ((i & 1) && (i+1 < b)){
c = this.buffer.readUInt8(this.pos++);
}
low_nibble = !low_nibble;
}
if ((((b+1) >> 1) & 1 ) == 1){
this.pos++
}
}
}else{//encoded mode
for (var i = 0; i < a; i++) {
if (low_nibble) {
setPixelData.call(this, (b & 0x0f));
} else {
setPixelData.call(this, (b & 0xf0)>>4);
}
low_nibble = !low_nibble;
}
}
}
function setPixelData(rgbIndex){
var rgb = this.palette[rgbIndex];
this.data[location] = 0;
this.data[location + 1] = rgb.blue;
this.data[location + 2] = rgb.green;
this.data[location + 3] = rgb.red;
location+=4;
}
}else{
var xlen = Math.ceil(this.width/2);
var mode = xlen%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 < xlen; x++) {
var b = this.buffer.readUInt8(this.pos++);
var location = line * this.width * 4 + x*2*4;
var before = b>>4;
var after = b&0x0F;
var rgb = this.palette[before];
this.data[location] = 0;
this.data[location + 1] = rgb.blue;
this.data[location + 2] = rgb.green;
this.data[location + 3] = rgb.red;
if(x*2+1>=this.width)break;
rgb = this.palette[after];
this.data[location+4] = 0;
this.data[location+4 + 1] = rgb.blue;
this.data[location+4 + 2] = rgb.green;
this.data[location+4 + 3] = rgb.red;
}
if (mode != 0){
this.pos+=(4 - mode);
}
}
}
};
BmpDecoder.prototype.bit8 = function() {
//RLE-8
if(this.compress == 1){
this.data.fill(0xff);
var location = 0;
var lines = this.bottom_up?this.height-1:0;
while(location<this.data.length){
var a = this.buffer.readUInt8(this.pos++);
var b = this.buffer.readUInt8(this.pos++);
//absolute mode
if(a == 0){
if(b == 0){//line end
if(this.bottom_up){
lines--;
}else{
lines++;
}
location = lines*this.width*4;
continue;
}else if(b == 1){//image end
break;
}else if(b ==2){
//offset x,y
var x = this.buffer.readUInt8(this.pos++);
var y = this.buffer.readUInt8(this.pos++);
if(this.bottom_up){
lines-=y;
}else{
lines+=y;
}
location +=(y*this.width*4+x*4);
}else{
for(var i=0;i<b;i++){
var c = this.buffer.readUInt8(this.pos++);
setPixelData.call(this, c);
}
if(b&1 == 1){
this.pos++;
}
}
}else{//encoded mode
for (var i = 0; i < a; i++) {
setPixelData.call(this, b);
}
}
}
function setPixelData(rgbIndex){
var rgb = this.palette[rgbIndex];
this.data[location] = 0;
this.data[location + 1] = rgb.blue;
this.data[location + 2] = rgb.green;
this.data[location + 3] = rgb.red;
location+=4;
}
}else {
var mode = this.width % 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++) {
var b = this.buffer.readUInt8(this.pos++);
var location = line * this.width * 4 + x * 4;
if (b < this.palette.length) {
var rgb = this.palette[b];
this.data[location] = 0;
this.data[location + 1] = rgb.blue;
this.data[location + 2] = rgb.green;
this.data[location + 3] = rgb.red;
} else {
this.data[location] = 0;
this.data[location + 1] = 0xFF;
this.data[location + 2] = 0xFF;
this.data[location + 3] = 0xFF;
}
}
if (mode != 0) {
this.pos += (4 - mode);
}
}
}
};
BmpDecoder.prototype.bit15 = function() {
var dif_w =this.width % 3;
var _11111 = parseInt("11111", 2),_1_5 = _11111;
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 & _1_5) / _1_5 * 255 | 0;
var green = (B >> 5 & _1_5 ) / _1_5 * 255 | 0;
var red = (B >> 10 & _1_5) / _1_5 * 255 | 0;
var alpha = (B>>15)?0xFF:0x00;
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;
}
//skip extra bytes
this.pos += dif_w;
}
};
BmpDecoder.prototype.bit16 = function() {
var dif_w =(this.width % 2)*2;
//default xrgb555
this.maskRed = 0x7C00;
this.maskGreen = 0x3E0;
this.maskBlue =0x1F;
this.mask0 = 0;
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;
}
var ns=[0,0,0];
for (var i=0;i<16;i++){
if ((this.maskRed>>i)&0x01) ns[0]++;
if ((this.maskGreen>>i)&0x01) ns[1]++;
if ((this.maskBlue>>i)&0x01) ns[2]++;
}
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;
};