Re: [png-mng-implement] png_set_cHRM_fixed

[Glenn Randers-P. <gl...@co...>]

At 04:22 PM 11/30/2007 -0500, you wrote:
>
>Hi guys.
>
>I think that there is a bug in 1.2.23 pngset.c,  png_set_cHRM_fixed()
>
>The arguments to the function should already be in fixed point. This 
>means two things to me. First, the section wrapped with
>
>#ifdef PNG_FLOATING_POINT_SUPPORTED
>   if (white_x > (double) PNG_UINT_31_MAX ||
>       white_y > (double) PNG_UINT_31_MAX ||
>         red_x > (double) PNG_UINT_31_MAX ||
>         red_y > (double) PNG_UINT_31_MAX ||
>       green_x > (double) PNG_UINT_31_MAX ||
>       green_y > (double) PNG_UINT_31_MAX ||
>        blue_x > (double) PNG_UINT_31_MAX ||
>        blue_y > (double) PNG_UINT_31_MAX)
>#else
>
>does not belong there and can be removed (again, the values should be in 
>fixed so the comparison does not make sense).

OK.

>Second, the test for:
> png_warning(png_ptr,
>        "Ignoring attempt to set chromaticity value exceeding 21474.83");
>is wrong because it is not testing for that value.....
>
>instead of:
>if (white_x > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
>       white_y > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
>         red_x > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
>         red_y > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
>       green_x > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
>       green_y > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
>        blue_x > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
>        blue_y > (png_fixed_point) PNG_UINT_31_MAX/100000L)
>
>it should be:
>   if (white_x > (png_fixed_point) 2147483000L ||
>       white_y > (png_fixed_point) 2147483000L ||
>         red_x > (png_fixed_point) 2147483000L ||
>         red_y > (png_fixed_point) 2147483000L ||
>       green_x > (png_fixed_point) 2147483000L ||
>       green_y > (png_fixed_point) 2147483000L ||
>        blue_x > (png_fixed_point) 2147483000L ||
>        blue_y > (png_fixed_point) 2147483000L)

PNG_UINT_31_MAX is 2147483647, and the division should get optimized away by the compiler preprocessor.

Glenn