image processing

**matsp** · 10-14-2007

What's this:

Code:

While Current_x < than Max_x;
array[x]<--array[x-255] 
// meant to invert colour , by changing pixel   value 
EndWhile;
While Current_y less than Max_y;
Array[y]<--array[y-255]; 
EndWhile;
new <-- Invert(array x y);

It looks like you are moving pixels around, rather than inverting the colour of the pixels.

--
Mats

**ICool** · 10-14-2007

Originally Posted by matsp

What's this:

Code:

While Current_x < than Max_x;
array[x]<--array[x-255] 
// meant to invert colour , by changing pixel   value 
EndWhile;
While Current_y less than Max_y;
Array[y]<--array[y-255]; 
EndWhile;
new <-- Invert(array x y);

It looks like you are moving pixels around, rather than inverting the colour of the pixels.

--
Mats

Well I'm not sure , that's what I thought , but maybe I should break it up into 3 colours ( the pixels i mean ) , and then do this for all 3 :

Code:

array[colour] = 255-array[colour];

**matsp** · 10-14-2007

Originally Posted by ICool

Well I'm not sure , that's what I thought , but maybe I should break it up into 3 colours ( the pixels i mean ) , and then do this for all 3 :

Code:

array[colour] = 255-array[colour];

Somthing like that, yes. Although I'd expect that you need to do something along the lines of:

Code:

pixel = array[y][x];
pixel.red = 255-pixel.red;
...

Of course, the actual process of splitting the colour will involve some shifting and masking with and, rather than accessing a struct.

--
Mats

**ICool** · 10-14-2007

Hmm , so you mean it is too difficult to split image into 3 colours ?

**matsp** · 10-14-2007

Originally Posted by ICool

Hmm , so you mean it is too difficult to split image into 3 colours ?

More like "not necessary" - but that's just my thoughts.

--
Mats

**ICool** · 10-14-2007

Do you know any other way to do it then ?

**taurus** · 10-14-2007

red is ((image_data[row][column]>>16)&0xff)
blue is ((image_data[row][column]>>8)&0xff)
green is ((image_data[row][column])&0xff)

**matsp** · 10-14-2007

Right, so you will need to split each pixel into red, green, blue and then manipulate[1], but you don't need to make an array of each of the three base colours (at least not if all you want to do is invert the colour).

[1] Although I did post a single operation that should be safe to perform on a whole pixel at a time[at least as long as there is no alpha value in the upper 8 bits]

--
Mats

**ICool** · 10-14-2007

I still dont understant how to use that

**matsp** · 10-14-2007

Originally Posted by ICool

I still dont understant how to use that

What don't you understand, and what have you done to understand it?

--
Mats

**ICool** · 10-14-2007

When I posted that I didn't understand I didn't see your post . When you say single operation you men this :
pixel = array[y][x];
pixel.red = 255-pixel.red;
...

**taurus** · 10-14-2007

hey ICool, check ur private messages

**ICool** · 10-14-2007

I'm not sure how to do that taurus , I think there is a function that he gives us that does it though , I haven't yet come to that part

**mike_g** · 10-14-2007

red is ((image_data[row][column]>>16)&0xff)
blue is ((image_data[row][column]>>8)&0xff)
green is ((image_data[row][column])&0xff)

You seem to have mixed up blue and green. Colour elements tend to go RGB.

**taurus** · 10-14-2007

Hi MATSP, got a question:
for this:

// This routine will put the image pixel data into the supplied matrix
// from top left to bottom right. You must ensure that enough space is
// available.
void ep100_lib_get_data(int data[EP100_LIB_MAX_X][EP100_LIB_MAX_Y]);

i just wanna c if i understand it. data is the name of the array and the things in the [][] are the size. now to set the array (data) to the image file pixels, i would do this?:
ep100_lib_get_data(data)
??
or wat?