我的问题是这样的:我想尝试制作一个白色的24位位图,但每次我写入bmp文件时,它都会给我白色的黑/白条纹。我不明白为什么?也许我跳过一些字节? 如果您想了解有关代码的更多信息,请询问。
设置设置:
void setup_settings( ) {
// information om billedet
pic.infoHeader.biSize = sizeof(BMP_InfoHeader);
pic.infoHeader.biBitCount = 24;
pic.infoHeader.biWidth = WIDTH; // Hoejte i pixels
pic.infoHeader.biHeight = HEIGH; // bredte i pixels
pic.infoHeader.biPlanes = 1;
pic.infoHeader.biCompression = 0;
pic.infoHeader.biSizeImage = WIDTH * HEIGH * (pic.infoHeader.biBitCount/8);
pic.infoHeader.biXPelsPerMeter = 0;
pic.infoHeader.biYPelsPerMeter = 0;
pic.infoHeader.biClrUsed = 0;
pic.infoHeader.biClrInportant = 0;
pic.fileHeader.bfType[0] = 'B';
pic.fileHeader.bfType[1] = 'M';
pic.fileHeader.bfReservered1 = pic.fileHeader.bfReservered2 = 0;
pic.fileHeader.bfOffBits = sizeof(BMP_FileHeader) + pic.infoHeader.biSize;
}
我的SaveBitmapFile的这个funktion定义是:
int SaveBitmapFile(const std::string filename, bit24* image){
// gem filen
std::ofstream writer(FileName.c_str(), std::ofstream::binary);
if(!writer.is_open()){
printf("Error: While Writing\n");
return -1;
}
writer.write(reinterpret_cast<char *>(&pic.fileHeader), sizeof(BMP_FileHeader) );
writer.write(reinterpret_cast<char *>(&pic.infoHeader), sizeof(BMP_InfoHeader) );
writer.write(reinterpret_cast<char*>(&image[0]), pic.infoHeader.biSizeImage);
writer.close();
return 0;
}
我的结构:
#pragma pack(1)
typedef struct{
uint32_t value : 24;
}bit24;
#pragma pack(0)
// Billedet
#pragma pack(1)
typedef struct{
unsigned int Width;
unsigned int Heigh;
bit24* RGB;
}Image;
#pragma pack(0)
typedef struct {
BMP_FileHeader fileHeader;
BMP_InfoHeader infoHeader;
Image data;
}BMP_Data;
我的源代码主要来源:
// the pic is a type of BMP_Data. sorry if i this is really messy.
int main( int argc, char *argv[] ){
setup_settings();
pic.data.Heigh = pic.infoHeader.biHeight;
pic.data.Width = pic.infoHeader.biWidth;
int bytesPerRGB = (pic.infoHeader.biBitCount/8);
//padded bytes?
int paddedBytes = ( pic.data.Width * bytesPerRGB) % 4;
printf("PaddedBytes: %d\n", paddedBytes);
pic.data.RGB = new bit24[ pic.data.Heigh * pic.data.Width * bytesPerRGB];
uint8_t r,g,b;
r = 0xFF;
g = 0xFF;
b = 0xFF;
/*
for( unsigned int y = 0; y < pic.data.Heigh; y++)
for( unsigned int x = 0; x < pic.data.Width; x++)
{
pic.data.RGB[x + (y*pic.data.Width )].value = ( (b << 0) | (g << 8) | (r << 16) );
}
*/
for( unsigned int i = 0; i < pic.data.Heigh * pic.data.Width * bytesPerRGB; i+=3){
pic.data.RGB[i ].value = ( (b << 0) | (g << 8) | (r << 16) );
}
SaveBitmapFile(FileName, pic.data.RGB);
delete [] pic.data.RGB;
return 0;
}
答案 0 :(得分:0)
您必须填写所有BitmapInfoHeader字段。 - 假设你想要24位位图:
BITMAPINFOHEADER bi =
{
sizeof(BITMAPINFOHEADER), // DWORD, = 40
WIDTH, // DWORD, image width in pix
HEIGHT, // DWORD, image width in pix
1, // WORD, planes MUST be 1
24,// WORD, num of bits per pixel
BI_RGB, // DWORD, (no compression = BI_RGB = 0)
0, // DWORD, sizeof image data, can be 0 if BI_RGB = 0
0, // DWORD, x-resolution
0, // DWORD, y-resolution
0, // DWORD, colors used (palette images only)
0, // DWORD, importand colors (palette images only)
};
(所以从N x 4宽度的图像开始 - 它们没有填充问题)
答案 1 :(得分:0)
好的,我找到了问题。
我将bit24更改为:
typedef struct{
uint8_t blue;
uint8_t green;
uint8_t red;
}RGB_Data;
从:
#pragma pack(1)
typedef struct{
uint32_t value : 24;
}bit24;
#pragma pack(0)
主要的一点变化:
for( unsigned int i = 0; i < pic.data.Heigh * pic.data.Width * bytesPerRGB; i++){
pic.data.RGB[i].blue = b;
pic.data.RGB[i].green = g;
pic.data.RGB[i].red = r;
}
它就像一个魅力。谢谢你的帮助:)