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# iGradient Struct Reference

A simple color gradient. More...

`#include <ivaria/gradient.h>`

Inheritance diagram for iGradient:

[legend]
List of all members.

## Public Member Functions

virtual void | Clear ()=0
| Clear all shades.
virtual csPtr< iGradientShades > | GetShades ()=0
| Get the array of shades.
virtual bool | Render (csRGBpixel *pal, size_t count, float begin=0.0f, float end=1.0f) const =0
| Interpolate the colors over a part of the gradient.
virtual bool | Render (csRGBcolor *pal, size_t count, float begin=0.0f, float end=1.0f) const =0
| Interpolate the colors over a part of the gradient.
virtual void | AddShade (const csGradientShade &shade)=0
| Add a shade.

## Detailed Description

A simple color gradient.

If you ever have worked with an image creation/manipulation program with a slightly higher niveau than Windows Paint then you probably know what this is.

Colors(here called 'shades') can be placed at arbitrary positions; although commonly a range of [0;1] is used, negative positions and positions larger than 1 are supported.

Shades contain actually two colors, a 'left' and 'right' one. You can think of this as, when approaching from one side, you'll get closer and closer to the respective color. If you step over a shade, you have the other color, but you're getting farther and farther from it (and towards the next color) when moving on. This feature can be used for sharp transitions; for smooth ones they are simply set to the same value.

This interface is implemented by csGradient.

Examples:

     csRef<iGradient> grad;
     // Rainbow-ish
     grad->AddShade (csColor4 (1.0f, 0.0f, 0.0f, 1.0f), 0.0f);
     grad->AddShade (csColor4 (1.0f, 1.0f, 0.0f, 1.0f), 0.2f);
     grad->AddShade (csColor4 (0.0f, 1.0f, 0.0f, 1.0f), 0.4f);
     grad->AddShade (csColor4 (0.0f, 1.0f, 1.0f, 1.0f), 0.6f);
     grad->AddShade (csColor4 (0.0f, 0.0f, 1.0f, 1.0f), 0.8f);
     grad->AddShade (csColor4 (1.0f, 0.0f, 1.0f, 1.0f), 1.0f);

     // German flag
     grad->Clear ();
     grad->AddShade (csColor4 (0.0f, 0.0f, 0.0f, 1.0f), 0.0f);
     grad->AddShade (csColor4 (0.0f, 0.0f, 0.0f, 1.0f),
       csColor4 (1.0f, 0.0f, 0.0f, 1.0f), 0.33f);
     grad->AddShade (csColor4 (1.0f, 0.0f, 0.0f, 1.0f),
      csColor4 (1.0f, 1.0f, 0.0f, 1.0f),
      0.66f);
     grad->AddShade (csColor4 (1.0f, 1.0f, 0.0f, 1.0f), 1.0f);

Todo:
  More shade management (e.g. getting, deleting of single shades.)

Definition at line 127 of file gradient.h.

## Member Function Documentation

virtual void iGradient::AddShade | ( | const csGradientShade & | shade | ) | `[pure virtual]`

Add a shade.

Implemented in csGradient.

virtual void iGradient::Clear | ( |  | ) | `[pure virtual]`

Clear all shades.

Implemented in csGradient.

virtual csPtr<iGradientShades> iGradient::GetShades | ( |  | ) | `[pure virtual]`

Get the array of shades.

Implemented in csGradient.

virtual bool iGradient::Render | ( | csRGBpixel * | pal,
|  | size_t | count,
|  | float | begin = `0.0f`,
|  | float | end = `1.0f` |
| ) |  |  | const`[pure virtual]`

Interpolate the colors over a part of the gradient.

Parameters:

  | pal | Array of csRGBpixel the gradient should be rendered to.
  | count | Number of `palette` entries to render.
  | begin | Start position. Can be anywhere in the gradient.
  | end | End position. Can be anywhere in the gradient.

Remarks:
  At least 1 shade has to be present in the gradient to have this function succeed.

  Makes heavy use of floating point calculations, so you might want to use this function in a precalc phase.

  `begin` doesn't have to be smaller than `end`.

  `begin` and `end` can both lie completely 'outside' the gradient (i.e. both smaller/large than the first resp. last shade's position.)

Implemented in csGradient.

virtual bool iGradient::Render | ( | csRGBcolor * | pal,
|  | size_t | count,
|  | float | begin = `0.0f`,
|  | float | end = `1.0f` |
| ) |  |  | const`[pure virtual]`

Interpolate the colors over a part of the gradient.

Parameters:

  | pal | Array of csRGBcolor the gradient should be rendered to.
  | count | Number of `palette` entries to render.
  | begin | Start position. Can be anywhere in the gradient.
  | end | End position. Can be anywhere in the gradient.

Remarks:
  At least 1 shade has to be present in the gradient to have this function succeed.

  Makes heavy use of floating point calculations, so you might want to use this function in a precalc phase.

  `begin` doesn't have to be smaller than `end`.

  `begin` and `end` can both lie completely 'outside' the gradient (i.e. both smaller/large than the first resp. last shade's position.)

Implemented in csGradient.

The documentation for this struct was generated from the following file:

- ivaria/gradient.h