Question

请任何人帮我转换C中的这个Android代码。我想在C NDK中做这个部分。这是我到目前为止所尝试的。我无法转换android的getPixel()和setPixel()方法。请参阅下面的代码。

JNIEXPORT jobject JNICALL
Java_com_test_mypic_StylePreviewActivity_mergeBitmaps(JNIEnv *env, jobject instance,
                                                                      jobject bm, jobject filter) {
    AndroidBitmapInfo bm1;
    AndroidBitmap_getInfo(env, bm, &bm1);

    AndroidBitmapInfo filter1;
    AndroidBitmap_getInfo(env, filter, &filter1);

    int width = bm1.width;
    int height = bm1.height;
    int w2 = filter1.width;
    int h2 = filter1.height;
    float scaleX = (float) w2 / (float) width;

    Bitmap result = Bitmap.createBitmap(w2, h2, ANDROID_BITMAP_FORMAT_RGB_565);

    void* bitmapPixels;
    AndroidBitmap_lockPixels(env, bm, &bitmapPixels);

    for (int x = 0; x < w2; x++) {
        for (int y = 0; y < h2 && y < height; y++) {
            int xx =(int) ((float) x / scaleX);
            int yy = (int) ((float) y / scaleX);
            int pixel = bm1.getPixel(xx, yy);
            int fp = filter1.getPixel(x, y);

            int alpha = (fp & 0xFF000000) >> 24;

            if (alpha == 0) {
                result.setPixel(x, y, pixel);
            }
        }
    }
    result = Bitmap.createBitmap(result, 0, 0, width, height);
    return result;
}

在@Serhio的帮助下，我写了这个方法。但它似乎有所作为在这里错了。请有人检查一下。

   JNIEXPORT jobject JNICALL
Java_com_test_mypic_StylePreviewActivity_mergeBitmaps(JNIEnv *env, jobject instance,
                                                                      jobject bm, jobject filter, jobject result) {
    AndroidBitmapInfo bm1;
    AndroidBitmap_getInfo(env, bm, &bm1);

    AndroidBitmapInfo filter1;
    AndroidBitmap_getInfo(env, filter, &filter1);

//    AndroidBitmapInfo result1;
//    AndroidBitmap_getInfo(env, result, &result1);

    int width = bm1.width;
    int height = bm1.height;
    int w2 = filter1.width;
    int h2 = filter1.height;
    float scaleX = (float) w2 / (float) width;

    for (int x = 0; x < w2; x++) {
        for (int y = 0; y < h2 && y < height; y++) {
            int xx =(int) ((float) x / scaleX);
            int yy = (int) ((float) y / scaleX);
            int pixel = getPixel(env,bm, xx, yy);
            int fp = getPixel(env,filter,x, y);

            int alpha = (fp & 0xFF000000) >> 24;

            if (alpha == 0) {
                setPixel(env, result, x, y, pixel);
            }
        }
    }

    return result;
}

Answer 1

本机代码中没有$('[id*="DTE_field_"]').attr('id', function(i, oldId) { return oldId.replace('DTE_field_', ''); });的直接模拟。取而代之的是，通过getPixel()/setPixel()获取指向像素缓冲区的原始指针，然后您可以自由修改此缓冲区中的数据。要获取/设置单个像素，您可以使用下一个功能：

AndroidBitmap_lockPixels()

当然，您只需锁定一次缓冲区并循环遍历像素。

尽管如此，您的代码似乎应该执行应用于位图的掩码。可能只有通过使用适当的#include <stdint.h> #include <assert.h> #include <jni.h> #include <android/bitmap.h> uint32_t getPixel(JNIEnv *env, jobject bm, int x, int y) { AndroidBitmapInfo bi = {0}; uint8_t *pixelBuf; uint8_t a, r, g, b; AndroidBitmap_getInfo(env, bm, &bi); /* ensure that we fit into bounds */ assert(x >= 0 && x < bi.width && y >= 0 && y < bi.height); /* we support only one format at the moment */ assert(ANDROID_BITMAP_FORMAT_RGBA_8888 == bi.format); /* read pixel components */ AndroidBitmap_lockPixels(env, bm, (void **)&pixelBuf); r = pixelBuf[y * bi.stride + x * 4 + 0]; g = pixelBuf[y * bi.stride + x * 4 + 1]; b = pixelBuf[y * bi.stride + x * 4 + 2]; a = pixelBuf[y * bi.stride + x * 4 + 3]; AndroidBitmap_unlockPixels(env, bm); return a << 24 | r << 16 | g << 8 | b; } void setPixel(JNIEnv *env, jobject bm, int x, int y, uint32_t val) { AndroidBitmapInfo bi = {0}; uint8_t *pixelBuf; AndroidBitmap_getInfo(env, bm, &bi); /* ensure that we fit into bounds */ assert(x >= 0 && x < bi.width && y >= 0 && y < bi.height); /* we support only one format at the moment */ assert(ANDROID_BITMAP_FORMAT_RGBA_8888 == bi.format); /* read pixel components */ AndroidBitmap_lockPixels(env, bm, (void **)&pixelBuf); pixelBuf[y * bi.stride + x * 4 + 0] = (val >> 16) & 0xff; pixelBuf[y * bi.stride + x * 4 + 1] = (val >> 8) & 0xff; pixelBuf[y * bi.stride + x * 4 + 2] = (val >> 0) & 0xff; pixelBuf[y * bi.stride + x * 4 + 3] = (val >> 24) & 0xff; AndroidBitmap_unlockPixels(env, bm); }在位图驱动的画布上绘制，才能在java代码中完成。 See here。它将在本机代码中完成，因此性能会很好。

在Android NDK中将android代码转换为c

1 个答案: