效果图

指数5
指数15

指数40

原理

马赛克的原理很简单，就是取一个值，让这个值作为一个方格子的长宽，如40*40px的格子，取这个区域的平均R G B值，然后这个区域的所有像素点都是这个RGB值即可

源码

QImage applyMosaic(const QImage& oldImage, int blockSize) {if (oldImage.isNull() || blockSize <= 0) {return QImage(); // 返回空图片或处理错误}// 确保blockSize是偶数，并且不会使图像尺寸变得太小blockSize = (blockSize % 2 == 0) ? blockSize : blockSize + 1;if (oldImage.width() < blockSize || oldImage.height() < blockSize) {return oldImage; // 如果blockSize太大，直接返回原图}// 计算新图片的尺寸int newWidth = oldImage.width() / blockSize * blockSize;int newHeight = oldImage.height() / blockSize * blockSize;QImage newImage(newWidth, newHeight, oldImage.format());// 遍历每个块for (int y = 0; y < newHeight; y += blockSize) {for (int x = 0; x < newWidth; x += blockSize) {// 计算块的平均颜色QRgb averageColor = qRgb(0, 0, 0); // 初始化平均颜色为黑色int totalR = 0, totalG = 0, totalB = 0;int count = 0;for (int by = 0; by < blockSize && y + by < oldImage.height(); ++by) {for (int bx = 0; bx < blockSize && x + bx < oldImage.width(); ++bx) {QRgb pixel = oldImage.pixel(x + bx, y + by);totalR += qRed(pixel);totalG += qGreen(pixel);totalB += qBlue(pixel);++count;}}if (count > 0) { // 确保count不是0，避免除以0averageColor = qRgb(totalR / count, totalG / count, totalB / count);}// 用平均颜色填充整个块for (int by = 0; by < blockSize && y + by < newImage.height(); ++by) {for (int bx = 0; bx < blockSize && x + bx < newImage.width(); ++bx) {newImage.setPixel(x + bx, y + by, averageColor);}}}}return newImage;
}