matplotlib-devel Mailing List for matplotlib

On 05/26/2011 04:40 AM, Michael Droettboom wrote:
> On 05/25/2011 05:36 PM, Eric Firing wrote:
>> On 05/25/2011 10:53 AM, Dieter Schön wrote:
>>
>>> hi list,
>>>
>>> first, thanks for providing matplotlib, i am using it in several projects.
>>>
>>> i had problems with several png files and decided to upgrade libpng.
>>> this broke matplotlib.
>>> as you can see in the documentation of libpng15, it is no longer possible
>>> to directly access png_infop.
>>>
>>> i have created the following patch:
>>>
>> Dieter,
>>
>> Thank you, but the modification has already been made to the master
>> branch.  I did not consider this as a bug fix, so I applied it only to
>> master, not to the maintenance branch.
>>
> It seems to have been applied to the maintenance branch...  Maybe
> someone backported it?

Mike,

I think you did--unintentionally!  If you look at the graph with qgit 
(or presumably any other such tool) in the vicinity of your commits on 
May 6, you will see that this one

a50874b711983cba505ecdb2801c4996eccf3812

made v1.0.x branch off of master; the v1.0.x line was broken by the 
previous commit.  To confirm that this break had the effect of 
propagating the change in _png.cpp into what is now v1.0.x, you can look 
at the diff between two commits on "v1.0.x", one of which is a bit 
before the break, the other after:

git diff 069c21d 0e6dad src/_png.cpp

You will see that the file was changed.

Eric



>
> https://github.com/matplotlib/matplotlib/blob/v1.0.x/src/_png.cpp
>
> Mike

On 05/25/2011 05:36 PM, Eric Firing wrote:
> On 05/25/2011 10:53 AM, Dieter Schön wrote:
>    
>> hi list,
>>
>> first, thanks for providing matplotlib, i am using it in several projects.
>>
>> i had problems with several png files and decided to upgrade libpng.
>> this broke matplotlib.
>> as you can see in the documentation of libpng15, it is no longer possible
>> to directly access png_infop.
>>
>> i have created the following patch:
>>      
> Dieter,
>
> Thank you, but the modification has already been made to the master
> branch.  I did not consider this as a bug fix, so I applied it only to
> master, not to the maintenance branch.
>    
It seems to have been applied to the maintenance branch...  Maybe 
someone backported it?

https://github.com/matplotlib/matplotlib/blob/v1.0.x/src/_png.cpp

Mike

> Eric
>
>    
>> --- matplotlib-1.0.1/src/_png.cpp	2010-10-12 16:14:42.000000000 +0000
>> +++ matplotlib-1.0.1X/src/_png.cpp	2011-05-25 19:23:36.261752651 +0000
>> @@ -350,18 +350,21 @@
>>        png_set_sig_bytes(png_ptr, 8);
>>        png_read_info(png_ptr, info_ptr);
>>
>> -    png_uint_32 width = info_ptr->width;
>> -    png_uint_32 height = info_ptr->height;
>> +    png_uint_32 width = png_get_image_width(png_ptr, info_ptr);
>> +    png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
>>
>> -    int bit_depth = info_ptr->bit_depth;
>> +    int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
>>
>>        // Unpack 1, 2, and 4-bit images
>>        if (bit_depth<   8)
>>            png_set_packing(png_ptr);
>>
>> +    // this is needed several times, so safe it in a variable
>> +    png_byte color_type = png_get_color_type(png_ptr, info_ptr);
>> +
>>        // If sig bits are set, shift data
>>        png_color_8p sig_bit;
>> -    if ((info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)&&
>> +    if ((color_type != PNG_COLOR_TYPE_PALETTE)&&
>>            png_get_sBIT(png_ptr, info_ptr,&sig_bit))
>>        {
>>            png_set_shift(png_ptr, sig_bit);
>> @@ -374,13 +377,13 @@
>>        }
>>
>>        // Convert palletes to full RGB
>> -    if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
>> +    if (color_type == PNG_COLOR_TYPE_PALETTE)
>>        {
>>            png_set_palette_to_rgb(png_ptr);
>>        }
>>
>>        // If there's an alpha channel convert gray to RGB
>> -    if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
>> +    if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
>>        {
>>            png_set_gray_to_rgb(png_ptr);
>>        }
>> @@ -408,11 +411,11 @@
>>        npy_intp dimensions[3];
>>        dimensions[0] = height;  //numrows
>>        dimensions[1] = width;   //numcols
>> -    if (info_ptr->color_type&   PNG_COLOR_MASK_ALPHA)
>> +    if (color_type&   PNG_COLOR_MASK_ALPHA)
>>        {
>>            dimensions[2] = 4;     //RGBA images
>>        }
>> -    else if (info_ptr->color_type&   PNG_COLOR_MASK_COLOR)
>> +    else if (color_type&   PNG_COLOR_MASK_COLOR)
>>        {
>>            dimensions[2] = 3;     //RGB images
>>        }
>> @@ -421,7 +424,7 @@
>>            dimensions[2] = 1;     //Greyscale images
>>        }
>>        //For gray, return an x by y array, not an x by y by 1
>> -    int num_dims  = (info_ptr->color_type&   PNG_COLOR_MASK_COLOR) ? 3 : 2;
>> +    int num_dims  = (color_type&   PNG_COLOR_MASK_COLOR) ? 3 : 2;
>>
>>        double max_value = (1<<   ((bit_depth<   8) ? 8 : bit_depth)) - 1;
>>        PyArrayObject *A = (PyArrayObject *) PyArray_SimpleNew(
>>
>>
>> kind regards,
>> dieter
>>
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>
>
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-- 
Michael Droettboom
Science Software Branch
Space Telescope Science Institute
Baltimore, Maryland, USA