尝试添加：

CGContextSetInterpolationQuality(g, kCGInterpolationHigh);
CGContextSetRenderingIntent(g, kCGRenderingIntentDefault); 

之前：

CGContextDrawPDFPage(g, m_page);

我有一个类似的问题，添加上面的2个函数调用导致渲染使用少5倍的内存。可能是CGContextXXX绘图函数

I had a similar issue and adding the 2 function call above resulted in the rendering using 5x less memory. Might be a bug in the CGContextXXX drawing functions