当像素阵列为小型可编辑文本 AS3 时，不会生成 8 位 BMP 图像
8 bit BMP image not generated when pixel array is to small richeditable text AS3
不知道我的标题能不能表达出我现在面临的问题。
我会详细解释：
我正在从 RichEditableTexts 生成 bmp 图像，我正在使用位图 class 来获取允许我将其作为像素进行管理的 DisplayObject 属性。
那么我有这个功能：
/*
* Create a 8 bit BMP image as bytearray, with 256 color ( grayscale ).
*
*/
private static function encode( bitmapData:BitmapData ):ByteArray {
// bit depth configuration
var bytesPerPixel:int = 1;
var bitDepth:int = 8;
// image/file properties
var bmpWidth:int = bitmapData.width;
var bmpHeight:int = bitmapData.height;
var imageBytes:ByteArray = bitmapData.getPixels( bitmapData.rect );
/* Image from Preview size */
var imageSize:int = bmpWidth * bmpHeight * bytesPerPixel;
/* Image offset */
var imageDataOffset:int = 0x436;
/* File size */
var fileSize:int = imageSize + imageDataOffset;
// binary BMP data
var bmpBytes:ByteArray = new ByteArray();
bmpBytes.endian = Endian.LITTLE_ENDIAN; // byte order
// header information
bmpBytes.length = fileSize;
bmpBytes.writeByte(0x42); // B //0
bmpBytes.writeByte(0x4D); // M (BMP identifier) //1
bmpBytes.writeInt(fileSize); // file size //2
bmpBytes.position = 0x0A; // offset to image data
bmpBytes.writeInt( imageDataOffset ); //10 4 Bytes
bmpBytes.writeInt(0x28); // header size //14 4 Bytes
bmpBytes.position = 0x12; // width, height
bmpBytes.writeInt( bmpWidth ); //18 4 Bytes
bmpBytes.writeInt( bmpHeight ); //22 4 Bytes
bmpBytes.writeShort( 1 ); // planes (1) //26 2 Bytes
bmpBytes.writeShort( bitDepth ); // color depth //28 2 Bytes
bmpBytes.writeInt( 0 ); // compression type //30 4 Bytes
bmpBytes.writeInt( imageSize ); // image data size //34 4 Bytes
bmpBytes.writeInt( 0x2E23 ); // Horizontal resolution //38 4 Bytes
bmpBytes.writeInt( 0x2E23 ); // Vertical resolution //42 4 Bytes
bmpBytes.writeInt( 0x100 ); // Color in the palette
bmpBytes.position = 0x36; // start of color table
/* COLOR TABLE */
var table:uint = 256 * 4;
for (var i:uint = 0; i < table; i++) {
bmpBytes.writeByte( i ); //B
bmpBytes.writeByte( i ); //G
bmpBytes.writeByte( i ); //R
bmpBytes.writeByte( 0 ); //A
/*
* Grays are made of equal bytes, for example: #AAAAAA is gray.
*/
}
bmpBytes.position = imageDataOffset; // start of image data... byte 310 // 1078
// write pixel bytes in upside-down order
// ( as per BMP format )
var col:int = bmpWidth;
var row:int = bmpHeight;
var rowLength:int = col * bytesPerPixel; // Bytes per column based on Bit depth
// Writing bytes to new image vars
var writingOffset:int = 4 - ( bitDepth / 8 );
try {
// make sure we're starting at the
// beginning of the image data
imageBytes.position = 0;
// Tmp ByteArray to extract 32 bits per pixel
var tmpBytes:ByteArray;
// bottom row up
while (row--) {
/* hey += "LINE\n"; */
// from end of file up to imageDataOffset
tmpBytes = new ByteArray();
bmpBytes.position = imageDataOffset + ( row * rowLength );
// read through each column writing
// those bits to the image in normal
// left to rightorder
col = bmpWidth;
while (col--) {
// Extracting the 32 bits corresponding
// to a pixel per getPixels method ( always the same ).
imageBytes.readBytes( tmpBytes, 0, 4 );
// We just need one BYTE of the 4 that are in this array.
tmpBytes.position = 3;
// THIS IS THE INDEX ON OUR COLOR TABLE ( GRAYSCALE ).
bmpBytes.writeByte( tmpBytes.readUnsignedByte() );
}
}
} catch(error:Error) {
// end of file
Alert.show( error.toString(), "I/O BMP ERROR" );
}
// return BMP file
return bmpBytes;
}
这些是我制作图像的 DisplayObjects 示例：
第一张图片生成良好，但第二张图片生成失败...
如果我用 atom 打开第二个，看起来像这样：
为什么？
有人能看到我遗漏的东西吗...这只是...啊。
提前谢谢你:)
我发现我没有在需要时添加填充...
这是生成的代码。
private static function encode( bitmapData:BitmapData ):ByteArray {
var bytesPerPixel:int = 1;
var bitDepth:int = 8;
// image/file properties
var bmpWidth:int = bitmapData.width;
var bmpHeight:int = bitmapData.height;
var imageBytes:ByteArray = bitmapData.getPixels(bitmapData.rect);
var imageSize:int = imageBytes.length;
// Offsets
var imageDataOffset:int = 0x436;
var colorTableOffset:int = 0x36;
// Pixel array
var col:int = bmpWidth;
var row:int = bmpHeight;
var rowLength:int = col * bytesPerPixel; // 4 bytes per pixel (32 bit)
// Padding
var mod:int = ( rowLength % 4 ) != 0 ? 4 - ( rowLength % 4 ):0;
rowLength += mod;
// File size
var fileSize:int = imageSize + imageDataOffset + ( mod * row );
// binary BMP data
var bmpBytes:ByteArray = new ByteArray();
bmpBytes.endian = Endian.LITTLE_ENDIAN; // byte order
// header information
bmpBytes.length = fileSize;
// DIB header ( 40 bytes version )
bmpBytes.writeByte(0x42); // B
bmpBytes.writeByte(0x4D); // M (BMP identifier)
bmpBytes.writeInt( fileSize ); // file size
bmpBytes.position = 0x0A; // offset to image data
bmpBytes.writeInt(imageDataOffset);
bmpBytes.writeInt(0x28); // header size
bmpBytes.position = 0x12; // width, height
bmpBytes.writeInt(bmpWidth);
bmpBytes.writeInt(bmpHeight);
bmpBytes.writeShort(1); // planes (1)
bmpBytes.writeShort(bitDepth); // color depth (32 bit)
bmpBytes.writeInt(0); // compression type
bmpBytes.writeInt( ( imageSize + ( mod * row ) ) ); // image data size
bmpBytes.writeInt( 0x2E23 ); // Horizontal resolution
bmpBytes.writeInt( 0x2E23 ); // Vertical resolution
bmpBytes.writeInt( 0x100 ); // Color in the palette
bmpBytes.position = colorTableOffset; // start of color table...
/* COLOR TABLE */
for (var i:uint = 0; i < 1024; i++) {
bmpBytes.writeByte( i ); //B
bmpBytes.writeByte( i ); //G
bmpBytes.writeByte( i ); //R
bmpBytes.writeByte( 0 ); //A
}
/* Pixel array */
bmpBytes.position = imageDataOffset; // start of image data...
var imgBmp:ByteArray;
try {
// make sure we're starting at the
// beginning of the image data
imageBytes.position = 0;
// bottom row up
while (row--) {
imgBmp = new ByteArray();
// from end of file up to imageDataOffset
bmpBytes.position = imageDataOffset + row*rowLength;
// read through each column writing
// those bits to the image in normal
// left to rightorder
col = bmpWidth;
while (col--) {
imageBytes.readBytes ( imgBmp, 0, 4 );
bmpBytes .writeBytes( imgBmp, 1, 1 );
}
bmpBytes.position += mod;
}
}catch(error:Error){
// end of file
Alert.show( error.toString(), "EOF" );
}
// return BMP file
return bmpBytes;
}
根据 BMP 规范，每当行字节数不是 4 的倍数时，您必须添加填充以解决该问题。
如您所见，我简化了这段代码，但如果您能看到这些行：
// Padding
var mod:int = ( rowLength % 4 ) != 0 ? 4 - ( rowLength % 4 ):0;
rowLength += mod;
我正在根据实际的行长度调整我的行长度。
那么，后面写的时候只要"take in count"多出来的字节就可以了：
bmpBytes.position += mod;
填充字节时：
/* Pixel array */
bmpBytes.position = imageDataOffset; // start of image data...
var imgBmp:ByteArray;
try {
// make sure we're starting at the
// beginning of the image data
imageBytes.position = 0;
// bottom row up
while (row--) {
imgBmp = new ByteArray();
// from end of file up to imageDataOffset
bmpBytes.position = imageDataOffset + row*rowLength;
// read through each column writing
// those bits to the image in normal
// left to rightorder
col = bmpWidth;
while (col--) {
imageBytes.readBytes ( imgBmp, 0, 4 );
bmpBytes .writeBytes( imgBmp, 1, 1 );
}
bmpBytes.position += mod;
}
}catch(error:Error){
不知道我的标题能不能表达出我现在面临的问题。 我会详细解释：
我正在从 RichEditableTexts 生成 bmp 图像，我正在使用位图 class 来获取允许我将其作为像素进行管理的 DisplayObject 属性。
那么我有这个功能：
/*
* Create a 8 bit BMP image as bytearray, with 256 color ( grayscale ).
*
*/
private static function encode( bitmapData:BitmapData ):ByteArray {
// bit depth configuration
var bytesPerPixel:int = 1;
var bitDepth:int = 8;
// image/file properties
var bmpWidth:int = bitmapData.width;
var bmpHeight:int = bitmapData.height;
var imageBytes:ByteArray = bitmapData.getPixels( bitmapData.rect );
/* Image from Preview size */
var imageSize:int = bmpWidth * bmpHeight * bytesPerPixel;
/* Image offset */
var imageDataOffset:int = 0x436;
/* File size */
var fileSize:int = imageSize + imageDataOffset;
// binary BMP data
var bmpBytes:ByteArray = new ByteArray();
bmpBytes.endian = Endian.LITTLE_ENDIAN; // byte order
// header information
bmpBytes.length = fileSize;
bmpBytes.writeByte(0x42); // B //0
bmpBytes.writeByte(0x4D); // M (BMP identifier) //1
bmpBytes.writeInt(fileSize); // file size //2
bmpBytes.position = 0x0A; // offset to image data
bmpBytes.writeInt( imageDataOffset ); //10 4 Bytes
bmpBytes.writeInt(0x28); // header size //14 4 Bytes
bmpBytes.position = 0x12; // width, height
bmpBytes.writeInt( bmpWidth ); //18 4 Bytes
bmpBytes.writeInt( bmpHeight ); //22 4 Bytes
bmpBytes.writeShort( 1 ); // planes (1) //26 2 Bytes
bmpBytes.writeShort( bitDepth ); // color depth //28 2 Bytes
bmpBytes.writeInt( 0 ); // compression type //30 4 Bytes
bmpBytes.writeInt( imageSize ); // image data size //34 4 Bytes
bmpBytes.writeInt( 0x2E23 ); // Horizontal resolution //38 4 Bytes
bmpBytes.writeInt( 0x2E23 ); // Vertical resolution //42 4 Bytes
bmpBytes.writeInt( 0x100 ); // Color in the palette
bmpBytes.position = 0x36; // start of color table
/* COLOR TABLE */
var table:uint = 256 * 4;
for (var i:uint = 0; i < table; i++) {
bmpBytes.writeByte( i ); //B
bmpBytes.writeByte( i ); //G
bmpBytes.writeByte( i ); //R
bmpBytes.writeByte( 0 ); //A
/*
* Grays are made of equal bytes, for example: #AAAAAA is gray.
*/
}
bmpBytes.position = imageDataOffset; // start of image data... byte 310 // 1078
// write pixel bytes in upside-down order
// ( as per BMP format )
var col:int = bmpWidth;
var row:int = bmpHeight;
var rowLength:int = col * bytesPerPixel; // Bytes per column based on Bit depth
// Writing bytes to new image vars
var writingOffset:int = 4 - ( bitDepth / 8 );
try {
// make sure we're starting at the
// beginning of the image data
imageBytes.position = 0;
// Tmp ByteArray to extract 32 bits per pixel
var tmpBytes:ByteArray;
// bottom row up
while (row--) {
/* hey += "LINE\n"; */
// from end of file up to imageDataOffset
tmpBytes = new ByteArray();
bmpBytes.position = imageDataOffset + ( row * rowLength );
// read through each column writing
// those bits to the image in normal
// left to rightorder
col = bmpWidth;
while (col--) {
// Extracting the 32 bits corresponding
// to a pixel per getPixels method ( always the same ).
imageBytes.readBytes( tmpBytes, 0, 4 );
// We just need one BYTE of the 4 that are in this array.
tmpBytes.position = 3;
// THIS IS THE INDEX ON OUR COLOR TABLE ( GRAYSCALE ).
bmpBytes.writeByte( tmpBytes.readUnsignedByte() );
}
}
} catch(error:Error) {
// end of file
Alert.show( error.toString(), "I/O BMP ERROR" );
}
// return BMP file
return bmpBytes;
}
这些是我制作图像的 DisplayObjects 示例：
第一张图片生成良好，但第二张图片生成失败...
如果我用 atom 打开第二个，看起来像这样：
为什么？ 有人能看到我遗漏的东西吗...这只是...啊。
提前谢谢你:)
我发现我没有在需要时添加填充... 这是生成的代码。
private static function encode( bitmapData:BitmapData ):ByteArray {
var bytesPerPixel:int = 1;
var bitDepth:int = 8;
// image/file properties
var bmpWidth:int = bitmapData.width;
var bmpHeight:int = bitmapData.height;
var imageBytes:ByteArray = bitmapData.getPixels(bitmapData.rect);
var imageSize:int = imageBytes.length;
// Offsets
var imageDataOffset:int = 0x436;
var colorTableOffset:int = 0x36;
// Pixel array
var col:int = bmpWidth;
var row:int = bmpHeight;
var rowLength:int = col * bytesPerPixel; // 4 bytes per pixel (32 bit)
// Padding
var mod:int = ( rowLength % 4 ) != 0 ? 4 - ( rowLength % 4 ):0;
rowLength += mod;
// File size
var fileSize:int = imageSize + imageDataOffset + ( mod * row );
// binary BMP data
var bmpBytes:ByteArray = new ByteArray();
bmpBytes.endian = Endian.LITTLE_ENDIAN; // byte order
// header information
bmpBytes.length = fileSize;
// DIB header ( 40 bytes version )
bmpBytes.writeByte(0x42); // B
bmpBytes.writeByte(0x4D); // M (BMP identifier)
bmpBytes.writeInt( fileSize ); // file size
bmpBytes.position = 0x0A; // offset to image data
bmpBytes.writeInt(imageDataOffset);
bmpBytes.writeInt(0x28); // header size
bmpBytes.position = 0x12; // width, height
bmpBytes.writeInt(bmpWidth);
bmpBytes.writeInt(bmpHeight);
bmpBytes.writeShort(1); // planes (1)
bmpBytes.writeShort(bitDepth); // color depth (32 bit)
bmpBytes.writeInt(0); // compression type
bmpBytes.writeInt( ( imageSize + ( mod * row ) ) ); // image data size
bmpBytes.writeInt( 0x2E23 ); // Horizontal resolution
bmpBytes.writeInt( 0x2E23 ); // Vertical resolution
bmpBytes.writeInt( 0x100 ); // Color in the palette
bmpBytes.position = colorTableOffset; // start of color table...
/* COLOR TABLE */
for (var i:uint = 0; i < 1024; i++) {
bmpBytes.writeByte( i ); //B
bmpBytes.writeByte( i ); //G
bmpBytes.writeByte( i ); //R
bmpBytes.writeByte( 0 ); //A
}
/* Pixel array */
bmpBytes.position = imageDataOffset; // start of image data...
var imgBmp:ByteArray;
try {
// make sure we're starting at the
// beginning of the image data
imageBytes.position = 0;
// bottom row up
while (row--) {
imgBmp = new ByteArray();
// from end of file up to imageDataOffset
bmpBytes.position = imageDataOffset + row*rowLength;
// read through each column writing
// those bits to the image in normal
// left to rightorder
col = bmpWidth;
while (col--) {
imageBytes.readBytes ( imgBmp, 0, 4 );
bmpBytes .writeBytes( imgBmp, 1, 1 );
}
bmpBytes.position += mod;
}
}catch(error:Error){
// end of file
Alert.show( error.toString(), "EOF" );
}
// return BMP file
return bmpBytes;
}
根据 BMP 规范，每当行字节数不是 4 的倍数时，您必须添加填充以解决该问题。
如您所见，我简化了这段代码，但如果您能看到这些行：
// Padding
var mod:int = ( rowLength % 4 ) != 0 ? 4 - ( rowLength % 4 ):0;
rowLength += mod;
我正在根据实际的行长度调整我的行长度。 那么，后面写的时候只要"take in count"多出来的字节就可以了：
bmpBytes.position += mod;
填充字节时：
/* Pixel array */
bmpBytes.position = imageDataOffset; // start of image data...
var imgBmp:ByteArray;
try {
// make sure we're starting at the
// beginning of the image data
imageBytes.position = 0;
// bottom row up
while (row--) {
imgBmp = new ByteArray();
// from end of file up to imageDataOffset
bmpBytes.position = imageDataOffset + row*rowLength;
// read through each column writing
// those bits to the image in normal
// left to rightorder
col = bmpWidth;
while (col--) {
imageBytes.readBytes ( imgBmp, 0, 4 );
bmpBytes .writeBytes( imgBmp, 1, 1 );
}
bmpBytes.position += mod;
}
}catch(error:Error){