[3/3] gdiplus: Make GdipInvertMatrix test pass on native

[Nikolay Sivov]

James Hawkins wrote:
> On Sat, Jul 12, 2008 at 4:12 PM, Nikolay Sivov <bunglehead at gmail.com> wrote:
>   
>> Changelog:
>>    - Make GdipInvertMatrix test pass on native
>>
>> ---
>>  dlls/gdiplus/tests/matrix.c |   23 +++++++++++++++++------
>>  1 files changed, 17 insertions(+), 6 deletions(-)
>>
>> diff --git a/dlls/gdiplus/tests/matrix.c b/dlls/gdiplus/tests/matrix.c
>> index 16c1517..daf61ea 100644
>> --- a/dlls/gdiplus/tests/matrix.c
>> +++ b/dlls/gdiplus/tests/matrix.c
>> @@ -27,6 +27,19 @@
>>
>>  #define expect(expected, got) ok(got == expected, "Expected %.8x, got %.8x\n", expected, got)
>>
>> +/* compare matrix data with some tolerance */
>> +BOOL m_equalf(REAL *m1, REAL *m2)
>> +{
>> +    BOOL ret = TRUE;
>> +    INT i;
>> +
>> +    for(i = 0; i < 6; i++){
>> +        ret = ret && (fabsf(m1[i] - m2[i]) < 1e-5);
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>>  static void test_constructor_destructor(void)
>>  {
>>     GpStatus status;
>> @@ -119,12 +132,12 @@ static void test_isinvertible(void)
>>     GdipDeleteMatrix(matrix);
>>  }
>>
>> +static REAL minverted[] = {1.0/9.0, 2.0/9.0, 4.0/9.0, -1.0/9.0, -2.0, -1.0};
>>  static void test_invert(void)
>>  {
>>     GpStatus status;
>>     GpMatrix *matrix = NULL;
>> -    GpMatrix *inverted = NULL;
>> -    BOOL equal;
>> +    REAL mdata[6];
>>
>>     /* NULL */
>>     status = GdipInvertMatrix(NULL);
>> @@ -141,11 +154,9 @@ static void test_invert(void)
>>     status = GdipInvertMatrix(matrix);
>>     expect(Ok, status);
>>
>> -    GdipCreateMatrix2(1.0/9.0, 2.0/9.0, 4.0/9.0, -1.0/9.0, -2.0, -1.0, &inverted);
>> -    GdipIsMatrixEqual(matrix, inverted, &equal);
>> -    expect(TRUE, equal);
>> +    GdipGetMatrixElements(matrix, mdata);
>> +    expect(TRUE, m_equalf(mdata, minverted));
>>
>>     
>
> Why are you creating a new function that allows tolerance when you
> control the matrix you're comparing it to?  Allowing slop is
> acceptable in some circumstances, but not in this case, when there is
> one exact value (or matrix of values) returned.
Of course there's only one value of inverted matrix. GDI+ uses floating 
point values for matrix elements so don't you think the result could be 
slightly different due different calculation algorithms?