GraphUtil unit

Contains routines and types used when drawing graphics.

graphutil.pp contains routines and types used when drawing graphics. They focus primarily on converting colors and drawing gradients, scroll bars, and arrows.

It includes routines used to convert between both the HSL (hue, saturation, lightness) and HSV (hue, saturation, brightness value) alternative representations of the RGB color model.

HSV models the way different colors mix together, with the saturation dimension resembling various tints of brightly colored paint, and the value dimension resembling the mixture of those paints with varying amounts of black or white paint.

HSL places saturated colors around a circle with a lightness value of 0.5, where a lightness value of 0 or 1 is fully black or white (respectively).

GraphUtil is used in the Lazarus IDE, in LCL WidgetSet components, and optional Lazarus components like FPReport, SynEdit, and TAChart.

graphutil.pp is part of the Lazarus Component Library ( LCL).

Procedures and functions

`AntiAliasedStretchDrawBitmap`	procedure	Stretch-draws a bitmap using anti-aliased drawing.
`BitmapGrayscale`	procedure	Converts a bitmap to grayscale taking filtering parameters into account.
`ColorAdjustLuma`	function
`ColorHLSToRGB`	function
`ColorIsDark`	function
`ColorRGBToHLS`	procedure	Converts an RGB color value to Hue, Luminance, and Saturation values.
`ColorToGray`	function	Converts a Lazarus TColor value to its grayscale equivalent.
`ColorToHLS`	procedure	Converts a TColor value to its Hue, Lightness, and Saturation values.
`ColorToHSV`	procedure	Converts a TColor value to Hue, Saturation, and brightness Values.
`ContrastColor`	function
`DrawArrow`	procedure	Draws a line with an arrow at the specified location on a canvas.
`DrawGradientWindow`	procedure	Draws a window with a Title using gradient coloring.
`DrawRotatedText`	procedure	Draws the provided text on the given canvas, rotated by an angle as specified by the canvas' Font.Orientation. Returns the smallest enclosing rectangle.
`DrawVerticalGradient`	procedure	Draws a gradient from top to bottom with parabolic color variation.
`GetHighLightColor`	function
`GetHValue`	function	Gets the Hue value from the specified TColor value.
`GetShadowColor`	function
`GetSValue`	function	Gets the Saturation value from the specified TColor value.
`GetVValue`	function	Gets the brightness value from the specified TColor value.
`HLStoColor`	function	Converts Hue, Lightness, and Saturation values to a TColor value.
`HLStoRGB`	procedure	Converts Hue, Lightness, and Saturation values to a RGB color values.
`HSVRangeToColor`	function
`HSVToColor`	function	Converts Hue, Saturation, and brightness values to a TColor value.
`HSVtoRGB`	procedure	Converts Hue, Saturation, and brightness values to RGB values.
`HSVtoRGBQuad`	function	Converts Hue, Saturation, and brightness values to a TRGBQuad value .
`HSVtoRGBRange`	procedure
`HSVtoRGBTriple`	function	Converts Hue, Saturation, and brightness values to a TRGBTriple value .
`NormalizeRect`	function	Ensures that coordinates in the rectangle are in the correct order.
`RGBtoHLS`	procedure	Converts RGB color values to Hue, Lightness, and Saturation values.
`RGBToHSV`	procedure	Converts RGB values to Hue, Saturation, and brightness values.
`RGBtoHSVRange`	procedure
`ScaleImg`	procedure	Scales the specified bitmap image to the required dimensions.
`WaveTo`	procedure	Draws a horizontal or vertical wave at the specified position to the given device context.
`WordWrap`	procedure	Splits the provided string AText at word boundaries to individual lines so that these lines, in pixels, are not longer than the given AMaxWidth.

Types

`TArrowType`	enumeration	Indicates the drawing style for an arrow.
`TScrollDirection`	enumeration	Enumerated type that indicates the direction for scrollbar arrows.

Constants

NiceArrowAngle constant

Uses

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.