Skip to main content

Colour

Colour space conversions and colour operations.

Function Mapping​

libvips CDart BindingPipeline MethodPipelineSpec
vips_colourspace()apiBindings.colourspace()pipeline.colourspace()spec.colourspace()
vips_linear1()apiBindings.linear1()pipeline.brightness() / contrast()spec.brightness() / spec.contrast()
vips_invert()apiBindings.invert()pipeline.invert()spec.invert()
vips_flatten()apiBindings.flatten()pipeline.flatten()spec.flatten()
vips_gamma()apiBindings.gamma()pipeline.gamma()spec.gamma()
vips_Lab2XYZ()colourBindings.lab2XYZ()--
vips_XYZ2Lab()colourBindings.xyz2Lab()--
vips_Lab2LCh()colourBindings.lab2LCh()--
vips_LCh2Lab()colourBindings.lch2Lab()--
vips_sRGB2scRGB()colourBindings.srgb2scrgb()--
vips_scRGB2sRGB()colourBindings.scrgb2srgb()--
vips_icc_import()colourBindings.iccImport()--
vips_icc_export()colourBindings.iccExport()--
vips_icc_transform()colourBindings.iccTransform()--

colourspace​

Convert to a target colour space.

C API​

int vips_colourspace(VipsImage *in, VipsImage **out, VipsInterpretation space, ...);

Dart Binding​

int colourspace(
  Pointer<VipsImage> in1,
  Pointer<Pointer<VipsImage>> out,
  int space,  // VipsInterpretation enum value
);

Pipeline API​

pipeline.colourspace(VipsInterpretation.sRGB)
pipeline.colourspace(VipsInterpretation.bw)  // Grayscale

Colour spaces (VipsInterpretation):

  • VipsInterpretation.sRGB - Standard RGB
  • VipsInterpretation.bw - Greyscale
  • VipsInterpretation.lab - CIE Lab
  • VipsInterpretation.xyz - CIE XYZ
  • VipsInterpretation.cmyk - CMYK

linear1​

Apply a linear transformation (brightness/contrast).

C API​

int vips_linear1(VipsImage *in, VipsImage **out, double a, double b, ...);

Formula: out = in * a + b

Dart Binding​

int linear1(
  Pointer<VipsImage> in1,
  Pointer<Pointer<VipsImage>> out,
  double a,  // Multiplier (contrast)
  double b,  // Offset (brightness)
);

Pipeline API​

// Brightness adjustment (>1.0 = brighter)
pipeline.brightness(1.2)

// Contrast adjustment (>1.0 = more contrast)
pipeline.contrast(1.2)

// Combined
pipeline.brightness(1.1).contrast(1.2)

invert​

Invert pixel values (negative image).

C API​

int vips_invert(VipsImage *in, VipsImage **out, ...);

Dart Binding​

int invert(
  Pointer<VipsImage> in1,
  Pointer<Pointer<VipsImage>> out,
);

Pipeline API​

pipeline.invert()

grayscale​

Convert to grayscale (convenience method).

Pipeline API​

pipeline.grayscale()
// Equivalent to:
pipeline.colourspace(VipsInterpretation.bw)