Animating a Color Display

The colors of an element are specified in the Colors properties of the element properties. There you can select either a predefined style color from the list box or a color in the color dialog.

The Color variables element property is used for the color animation of the element. When you pass variables to the properties, you can program color changes in the application code or configure a user input that results in a color change. A color constant or color variable in the code has the data type DWORD and is encoded according to the RGB color space or RGBA extension.

Color definition in RGBA color space

Important

The Activate semi-transparent drawing option is provided in the Visualization Manager. This option is enabled by default so that the Transparency property is available for all color definitions. With a programmatic color definition, the leading byte is interpreted as an alpha channel and therefore used as the transparency value of the color. When the option is cleared, the Transparency property is not available and the leading byte is ignored in color literals.

Color information in the code is specified as DWORD literals. The value is in the RGBA color space and is usually shown as a hexadecimal number. The value is coded with additive portions of red, green, and blue. It is appended with the alpha channel which determines the transparency of the color.

Byte order of a color literal

16#<TT><RR><GG><BB>

<TT> : 00 - FF      // Transparency in 256 levels
<RR> : 00 - FF      // Red in 256 levels
<GG> : 00 - FF      // Green in 256 levels
<BB> : 00 - FF      // Blue in 256 levels

The graduation value for transparency is 16#FF for opaque and 16#00 for transparent. For each color portion, one byte is reserved for 256 color graduations 16#FF to 16#00. 16#FF means 100% color portion and 16#00 means 0% color portion.

`<TT>`	Byte for the transparent graduation of `00-FF`
`<RR>`	Byte for the red portion of `00-FF`
`<GG>`	Byte for the green portion of `00-FF`
`<BB>`	Byte for the blue portion of `00-FF`

Example 10. Example

Table 2. Color literal

`16#FF0000FF`	Blue, opaque
`16#FF00FF00`	Green, opaque
`16#FFFFFF00`	Yellow. opaque
`16#88888888`	Gray, semitransparent
`16#88000000`	Black, semitransparent
`16#FFFF0000`	Red, opaque

Example 11. Example

Global declaration of color constants

Animating a visualization element in color

Create a standard project in CODESYS.

Declare global color constants in the POU tree.

{attribute 'qualified_only'}
VAR_GLOBAL CONSTANT
    gc_dwRed : DWORD := 16#FFFF0000;
    gc_dwGreen: DWORD := 16#FF00FF00;
    gc_dwYellow: DWORD := 16#FFFFFF00;
    gc_dwBlue: DWORD := 16#FF0000FF;        // Highly opaque
    gc_dwBlack : DWORD := 16#88000000;      // Semitransparent
END_VAR

In the device tree, declare local color variables in PLC_PRG.

VAR
    dwFillColor: DWORD := GVL.gc_dwGreen;
    dwFrameColor : DWORD := GVL.gc_dwBlack;
    dwAlarmColor : DWORD := GVL.gc_dwRed;
END_VAR

Declare a control variable.
```
bChangeColor : BOOL;
```
Declare an input variable in PLC_PRG.
```
bInput : BOOL;
```
Enable the visualization editor.
Drag a Rectangle element to the visualization editor.
The Properties view of the element opens.
Configure the properties of the rectangle as follows:
- Color variables, Normal state, Filling color property: PLC_PRG.dwFillColor
- Color variables, Normal state, Frame color property: PLC_PRG.dwFrameColor
- Color variables, Alarm state, Filling color property: PLC_PRG.dwAlarmColor
- Color variables, Toggle color property: <toggle/tap variable>
- Input configuration, Toggle, Variable property: PLC_PRG.bInput

Program the variables as follows:

PROGRAM PLC_PRG
VAR
    dwFillColor: DWORD := GVL.gc_dwGreen;
    dwFrameColor : DWORD := GVL.gc_dwBlack;
    dwAlarmColor : DWORD := GVL.gc_dwRed;

    bChangeColor : BOOL;
    bInput : BOOL;
END_VAR

IF bChangeColor = TRUE THEN
    dwFillColor := GVL.gc_dwYellow;
    dwFrameColor := GVL.gc_dwBlue;
ELSE
    dwFillColor:= GVL.gc_dwGreen;
    dwFrameColor := GVL.gc_dwBlack;
END_IF

The colors are initialized at runtime. If the variable bChangeColor is then forced to TRUE, the color display of the rectangle changes. When the rectangle is clicked in the visualization, the rectangle is displayed in alarm colors.