- #1

ktoz

- 171

- 12

Hi

I'm writing a newspaper page management application and am having trouble trying to directly calculate a "best fit" column/row breakdown for displaying pages into arbitrary rectangles.

The arbitrary rectangle in question is the content area of a window and can be resized at will by the user. The pages are a uniform fixed size and the problem is to calculate the best scale and column/row breakdown to display all the pages in the given rectangle with the least wasted space.

Here are the knowns:

vw = width of enclosing view

vh = height of enclosing view

pw = width of the page

ph = height of the page

pct = number of pages to be displayed in the view

Unknowns:

c = columns

r = rows

s = scaling factor

cw = cell width

ch = cell height

After a bit of trial and error, I found that the optimal solution exists when

1 - (c * pw * vh) / (r * ph * vw) = 0;

Where r equals

r = floor(pct / c);

r += (c * r - pct < 0) ? 1 : 0 ;

I wrote a C function that is fairly efficient, but was wondering if there is a more direct way to find the zero.

Here's the C function

Thanks for any help

I'm writing a newspaper page management application and am having trouble trying to directly calculate a "best fit" column/row breakdown for displaying pages into arbitrary rectangles.

The arbitrary rectangle in question is the content area of a window and can be resized at will by the user. The pages are a uniform fixed size and the problem is to calculate the best scale and column/row breakdown to display all the pages in the given rectangle with the least wasted space.

Here are the knowns:

vw = width of enclosing view

vh = height of enclosing view

pw = width of the page

ph = height of the page

pct = number of pages to be displayed in the view

Unknowns:

c = columns

r = rows

s = scaling factor

cw = cell width

ch = cell height

After a bit of trial and error, I found that the optimal solution exists when

1 - (c * pw * vh) / (r * ph * vw) = 0;

Where r equals

r = floor(pct / c);

r += (c * r - pct < 0) ? 1 : 0 ;

I wrote a C function that is fairly efficient, but was wondering if there is a more direct way to find the zero.

Here's the C function

Code:

```
for (c = 1; c < pct + 1; c++)
{
// calculate the number of rows
r = floor(pct / c);
r += (c * r - pct < 0) ? 1 : 0 ;
// test for zero cross
if (1 - (c * pw * vh) / (vr * ph * vw) < 0)
{
// found zero, decrement c and calculate scale
c--;
// calculate the scale
s = vw / (c * pw);
// set the cell dimensions
cw = s * pw;
ch = s * ph;
// since we've found the zero, exit the loop
break;
}
}
```

Thanks for any help

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