• Create Account

### #ActualAhmed Egyptian

Posted 13 March 2013 - 03:35 PM

Hi All,

I tried to figure out the meaning of that function, I couldn't, even tried on paper, but didn't get it. Would someone explain that to me ? If that's possible with Ascii text or some images would be so much appreciated.

static void inline resizeRow(uint32_t *dst, uint32_t *src, uint32_t pixelsPerRow)

{
uint8_t * pSrc8 = (uint8_t *)src;
uint8_t * pDest8 = (uint8_t *)dst;
int stride = pixelsPerRow * sizeof(uint32_t);
int x;
int r, g, b, a;

for (x=0; x<pixelsPerRow; x++)
{
r = pSrc8[0] + pSrc8[4] + pSrc8[stride+0] + pSrc8[stride+4];
g = pSrc8[1] + pSrc8[5] + pSrc8[stride+1] + pSrc8[stride+5];
b = pSrc8[2] + pSrc8[6] + pSrc8[stride+2] + pSrc8[stride+6];
a = pSrc8[3] + pSrc8[7] + pSrc8[stride+3] + pSrc8[stride+7];
pDest8[0] = (uint8_t)((r + 2)/4); // average with rounding
pDest8[1] = (uint8_t)((g + 2)/4);
pDest8[2] = (uint8_t)((b + 2)/4);
pDest8[3] = (uint8_t)((a + 2)/4);
pSrc8 += 8; // skip forward 2 source pixels
pDest8 += 4; // skip forward 1 destination pixel
}
}


### #2Ahmed Egyptian

Posted 13 March 2013 - 03:34 PM

Hi All,

I tried to figure out the meaning of that function, I couldn't, even tried on paper, but didn't get it. Would someone explain that to me ?

static void inline resizeRow(uint32_t *dst, uint32_t *src, uint32_t pixelsPerRow)

{
uint8_t * pSrc8 = (uint8_t *)src;
uint8_t * pDest8 = (uint8_t *)dst;
int stride = pixelsPerRow * sizeof(uint32_t);
int x;
int r, g, b, a;

for (x=0; x<pixelsPerRow; x++)
{
r = pSrc8[0] + pSrc8[4] + pSrc8[stride+0] + pSrc8[stride+4];
g = pSrc8[1] + pSrc8[5] + pSrc8[stride+1] + pSrc8[stride+5];
b = pSrc8[2] + pSrc8[6] + pSrc8[stride+2] + pSrc8[stride+6];
a = pSrc8[3] + pSrc8[7] + pSrc8[stride+3] + pSrc8[stride+7];
pDest8[0] = (uint8_t)((r + 2)/4); // average with rounding
pDest8[1] = (uint8_t)((g + 2)/4);
pDest8[2] = (uint8_t)((b + 2)/4);
pDest8[3] = (uint8_t)((a + 2)/4);
pSrc8 += 8; // skip forward 2 source pixels
pDest8 += 4; // skip forward 1 destination pixel
}
}


### #1Ahmed Egyptian

Posted 13 March 2013 - 03:33 PM

Hi All,

I tried to figure out the meaning of that function, I couldn't, even tried on paper, but didn't get it. Would someone explain that to me ?

static void inline resizeRow(uint32_t *dst, uint32_t *src, uint32_t pixelsPerRow)

{
uint8_t * pSrc8 = (uint8_t *)src;
uint8_t * pDest8 = (uint8_t *)dst;
int stride = pixelsPerRow * sizeof(uint32_t);
int x;
int r, g, b, a;

for (x=0; x<pixelsPerRow; x++)
{
r = pSrc8[0] + pSrc8[4] + pSrc8[stride+0] + pSrc8[stride+4];
g = pSrc8[1] + pSrc8[5] + pSrc8[stride+1] + pSrc8[stride+5];
b = pSrc8[2] + pSrc8[6] + pSrc8[stride+2] + pSrc8[stride+6];
a = pSrc8[3] + pSrc8[7] + pSrc8[stride+3] + pSrc8[stride+7];
pDest8[0] = (uint8_t)((r + 2)/4); // average with rounding
pDest8[1] = (uint8_t)((g + 2)/4);
pDest8[2] = (uint8_t)((b + 2)/4);
pDest8[3] = (uint8_t)((a + 2)/4);
pSrc8 += 8; // skip forward 2 source pixels
pDest8 += 4; // skip forward 1 destination pixel
}
}


PARTNERS