[Qgis-developer] How to color a raster with a color table with values From - To?

[SupportLists]

I tried that but QgsSingleBandPseudoColorRenderer is a class that does 
not seem to exists in 1.8.0

Carlos.

On 08/14/2012 12:25 AM, Etienne Tourigny wrote:
> Hi
>
> sorry if I have misled you, the code I was quoting is in 1.9 (dev
> version). Have a look at the code in 1.9, it should probably work with
> 1.8 but might require some changes.
>
> https://github.com/qgis/Quantum-GIS/blob/master/tests/src/core/testqgsrasterlayer.cpp
>
> //items to imitate old pseudo color renderer
>    QList<QgsColorRampShader::ColorRampItem> colorRampItems;
>    QgsColorRampShader::ColorRampItem firstItem;
>    firstItem.value = 0.0;
>    firstItem.color = QColor( "#0000ff" );
>    colorRampItems.append( firstItem );
> [...]
>    colorRampShader->setColorRampItemList( colorRampItems );
>
>
> Etienne
>
> On Mon, Aug 13, 2012 at 8:12 AM, SupportLists <supportlists at qlands.com> wrote:
>> Hi,
>>
>> I am using 1.8.0 but tests/src/core/testqgsrasterlayer.cpp is defined as:
>>
>> void TestQgsRasterLayer::pseudoColor()
>> {
>>    mpRasterLayer->setDrawingStyle( QgsRasterLayer::SingleBandPseudoColor );
>>    mpRasterLayer->setColorShadingAlgorithm( QgsRasterLayer::PseudoColorShader
>> );
>>    mpRasterLayer->setContrastEnhancementAlgorithm(
>>      QgsContrastEnhancement::StretchToMinimumMaximum, false );
>>    mpRasterLayer->setMinimumValue( mpRasterLayer->grayBandName(), 0.0, false
>> );
>>    mpRasterLayer->setMaximumValue( mpRasterLayer->grayBandName(), 10.0 );
>>    mpMapRenderer->setExtent( mpRasterLayer->extent() );
>>    QVERIFY( render( "raster_pseudo" ) );
>> }
>>
>> I cannot locate the code using ColorRampItem.
>>
>> Many thanks,
>> Carlos.
>>
>>
>> On 08/08/2012 08:07 PM, Etienne Tourigny wrote:
>>> Hi,
>>>
>>> which version of the api are you using? If you are using the
>>> development version (1.9), there is support for more flexible color
>>> ramps with rasters, using QgsVectorColorRampV2. Beware, however, that
>>> the api is going to suffer some changes in the near future. There are
>>> various recent threads on this subject in this mailing list.
>>>
>>> Another option (and the only available if using 1.8) is to follow the
>>> approach used in the rasterlayer test in
>>> tests/src/core/testqgsrasterlayer.cpp .
>>> TestQgsRasterLayer::pseudoColor() uses a ColorRampItem vector and
>>> calls colorRampShader->setColorRampItemList(items)
>>>
>>> Etienne
>>>
>>> On Wed, Aug 8, 2012 at 3:42 AM, SupportLists <supportlists at qlands.com>
>>> wrote:
>>>> Hi,
>>>>
>>>> I am using QGIS API to develop a custom application. Currently I'm using
>>>> QgsRasterLayer::PalettedColor + QgsRasterLayer::ColorRampShader  +
>>>> QgsColorRampShader::ColorRampItem to render a raster using a specific
>>>> color
>>>> map.
>>>>
>>>> Now, I need to render the raster with a colormap using value From - To
>>>> however, ColorRampItem struct only accepts one value. Is there another
>>>> way
>>>> around? Or, its it possible to create user defined DrawingStyles and
>>>> ColorShadingAlgorithms? If so how?
>>>>
>>>> Any help is very much appreciated.
>>>>
>>>> Regards,
>>>> Carlos.
>>>> _______________________________________________
>>>> Qgis-developer mailing list
>>>> Qgis-developer at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>
>>