NDK图形函数在某些机型下显示花屏的问题

NDK使用ANativeWindow渲染surface，

大致代码如下：

ANativeWindow *nativeWindow = ANativeWindow_fromSurface(env, surface);
if (nativeWindow == 0) {
	LOGE("ANativeWindow_window_from_surface error;env[0x%x] surface[0x%x]", env, surface);
	return NULL;
}

int err = ANativeWindow_setBuffersGeometry(nativeWindow, width, height, WINDOW_FORMAT_RGB_565);
if ( err < 0 ) {
	LOGE("ANativeWindow_setBuffersGeometry error");
	return NULL;
}


LOGI("AnativeSurface_Draw param invalid. %d | %d | %d | %d | %d | %d", env, NativeSurface, ImgData, dataLen, width, height);
if (env == NULL || NativeSurface == NULL || ImgData == NULL
			|| dataLen == 0 || width == 0 || height == 0) {
	LOGE("AnativeSurface_Draw param invalid. %d | %d | %d | %d | %d | %d", env, NativeSurface, ImgData, dataLen, width, height);
	return ;
}

ANativeWindow_Buffer windowBuffer;
int nlocked = ANativeWindow_lock((ANativeWindow*)NativeSurface, &windowBuffer, 0);
if (nlocked < 0) {
	LOGW("AnativeSurface lock error:%d", nlocked);
	return;
}

if (windowBuffer.bits != NULL) {
	memcpy(windowBuffer.bits, ImgData, dataLen);
}

ANativeWindow_unlockAndPost((ANativeWindow*)NativeSurface);

ANativeWindow_release((ANativeWindow*)NativeSurface);

翻了下native_window.h(development/ndk/platforms/android-x/include/android目录下)，对于windowBuffer的定义如下：

typedef struct ANativeWindow_Buffer {
    // The number of pixels that are show horizontally.
    int32_t width;

    // The number of pixels that are shown vertically.
    int32_t height;

    // The number of *pixels* that a line in the buffer takes in
    // memory.  This may be >= width.
    int32_t stride;

    // The format of the buffer.  One of WINDOW_FORMAT_*
    int32_t format;

    // The actual bits.
    void* bits;
    
    // Do not touch.
    uint32_t reserved[6];
} ANativeWindow_Buffer;

再次测试，发现所有有问题的机型，果然stride大于width。因此在拷贝的时候需要注意内存对齐。。

最后解决方案如下：

    if (windowBuffer.bits != NULL) {
    	//memcpy(windowBuffer.bits, ImgData, dataLen);
    	if (windowBuffer.width == windowBuffer.stride) {
    		memcpy(windowBuffer.bits, ImgData, dataLen);
    	} else {
    		for (int ii=0; ii < windowBuffer.height; ii++) {
    			char *srcPointer = ImgData + windowBuffer.width * ii * 2;
    			char *dstPointer = ((char *)windowBuffer.bits) + windowBuffer.stride * ii * 2;

    			memcpy(dstPointer, srcPointer, windowBuffer.width * 2);
    		}
    	}
    }