File size: 2,429 Bytes
bf237c2 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 |
/**
* @author shaozilee
*
* BMP format encoder,encode 24bit BMP
* Not support quality compression
*
*/
function BmpEncoder(imgData){
this.buffer = imgData.data;
this.width = imgData.width;
this.height = imgData.height;
this.extraBytes = this.width%4;
this.rgbSize = this.height*(3*this.width+this.extraBytes);
this.headerInfoSize = 40;
this.data = [];
/******************header***********************/
this.flag = "BM";
this.reserved = 0;
this.offset = 54;
this.fileSize = this.rgbSize+this.offset;
this.planes = 1;
this.bitPP = 24;
this.compress = 0;
this.hr = 0;
this.vr = 0;
this.colors = 0;
this.importantColors = 0;
}
BmpEncoder.prototype.encode = function() {
var tempBuffer = new Buffer(this.offset+this.rgbSize);
this.pos = 0;
tempBuffer.write(this.flag,this.pos,2);this.pos+=2;
tempBuffer.writeUInt32LE(this.fileSize,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.reserved,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.offset,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.headerInfoSize,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.width,this.pos);this.pos+=4;
tempBuffer.writeInt32LE(-this.height,this.pos);this.pos+=4;
tempBuffer.writeUInt16LE(this.planes,this.pos);this.pos+=2;
tempBuffer.writeUInt16LE(this.bitPP,this.pos);this.pos+=2;
tempBuffer.writeUInt32LE(this.compress,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.rgbSize,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.hr,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.vr,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.colors,this.pos);this.pos+=4;
tempBuffer.writeUInt32LE(this.importantColors,this.pos);this.pos+=4;
var i=0;
var rowBytes = 3*this.width+this.extraBytes;
for (var y = 0; y <this.height; y++){
for (var x = 0; x < this.width; x++){
var p = this.pos+y*rowBytes+x*3;
i++;//a
tempBuffer[p]= this.buffer[i++];//b
tempBuffer[p+1] = this.buffer[i++];//g
tempBuffer[p+2] = this.buffer[i++];//r
}
if(this.extraBytes>0){
var fillOffset = this.pos+y*rowBytes+this.width*3;
tempBuffer.fill(0,fillOffset,fillOffset+this.extraBytes);
}
}
return tempBuffer;
};
module.exports = function(imgData, quality) {
if (typeof quality === 'undefined') quality = 100;
var encoder = new BmpEncoder(imgData);
var data = encoder.encode();
return {
data: data,
width: imgData.width,
height: imgData.height
};
};
|