Contrast Effect

Increases or decreases the contrast of an image.

The CLSID for this effect is CLSID_D2D1Contrast.

The contrast function modifies each color channel value using two, piecewise quadratic polynomials that meet with slope continuity at the point (0.5, 0.5).

• Example Images
• Sample Code
• Effect Properties
• Requirements
• Related topics

Example Images

This example shows the output of the effect with maximum contrast applied (Contrast = 1.0).

Before

After

Sample Code

ComPtr<ID2D1Effect> contrastEffect;
m_d2dContext->CreateEffect(CLSID_D2D1Contrast, &contrastEffect);
 
contrastEffect->SetInput(0, bitmap);
contrastEffect->SetValue(D2D1_CONTRAST_PROP_CONTRAST, 0.5f);
contrastEffect->SetValue(D2D1_CONTRAST_PROP_CLAMP_INPUT, TRUE);
 
m_d2dContext->BeginDraw();
m_d2dContext->DrawImage(contrastEffect.Get());
m_d2dContext->EndDraw();

Effect Properties

The properties for the contrast effect are defined by the D2D1_CONTRAST_PROP enumeration.

Requirements

Related topics

ID2D1Effect