Question

我试图从二进制文件中保存为16位整数的数据构建QImages。我可以正常加载数据，但是当我使用QImage :: loadFromData（QBytearray ba）函数（返回false）时，我的程序失败，如下所示：

QBytearray frame;
QImage pic = QImage(256, 256, QImage::Format_RGB888);

for(int i = 0; i < height; i++) {
    for(int j = 0; j < width; j++) {
        // Access value of pixel at each location
        datum = store[i][j];

        for(int c = 0; c < 3; c++) {
            // Calculate colour at given pixel
            col = (255.0f * ((float)datum - (float)min) / ((float)(max - min)));
            // Assign colour value to the pixel
            frame[c+3*j+3*i*width] = ((unsigned char)col);
        }
    }
}

pic.loadFromData(frame);

我从之前编写的Java代码中重新利用了这个代码，这些代码完全符合预期（来自完全相同的数据）：

BufferedImage image = = new BufferedImage(256, 256, BufferedImage.TYPE_3BYTE_BGR);

byte[] data = image.getRaster().getDataBuffer();

for (j=0; j<height; j++) {
    for (i=0; i<width; i++) {
        //Find value of the pixels at the location
        datum=data[j][i];
        for (c=0; c<3; c++) {
            //Calculate the colour at the given pixel
            col=(255.0f*((float)datum-(float)min)/((float)(max-min)));
            //Assign the colour value to the pixel
            data[c+3*i+3*j*width] = (byte)col;
        } 
    }
}

任何人都可以帮我看看我错在哪里吗？我已经被困了好几天，而且都是出于想法。

Answer 1

好的，假设您实际上是在尝试为单个像素设置RGB值，在阅读QImage details之后，我发现您可以使用以下方法来实现：

value = qRgb(189, 149, 39); // 0xffbd9527
image.setPixel(1, 1, value);

所以，比如：

QImage pic = QImage(256, 256, QImage::Format_RGB888);
QRgb value;
int r,b,g;

for(int i = 0; i < height; i++) {
    for(int j = 0; j < width; j++) {
        // Access value of pixel at each location
        datum = store[i][j];
        //I get really confused what is going on here... you don't seem to be actually using `c` for the calculation?
        for(int c = 0; c < 3; c++) { //let's just pretend you set the ints r,b,g in here somewhere
            // Calculate colour at given pixel
            col = (255.0f * ((float)datum - (float)min) / ((float)(max - min)));
        }
        // Assign colour value to the pixel
        value = qRgb(r, g, b);
        pic.setPixel(i, j, value);
    }
}

从QBytearray创建QImage

1 个答案: