TIPCORNER - COLORDIALOG

by Alyce Watson

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We've taken advantage of the new colordialog in LB3 for the updated Open Source Editor. The syntax is:

colordialog color$, chosen$

The parameter color$ can be an empty string, but it must be included. The color chosen by the user is contained in the variable, chosen$ after the dialog is closed. The input parameter may be in one of two forms. It can be a named Liberty BASIC color, or a string containing the red, green, blue values of the desired color with which to seed the colordialog. Remember that this is a string, and that the values are NOT separated by commas.

color$="red"
or
color$="255 0 0"
colordialog color$, chosen$

The color specification can be placed directly into the colordialog:

colordialog "red", chosen$
or
colordialog "255 0 0", chosen$

Red, green and blue values must each be in the range of 0 to 255. 0 is the absence of a color, and 255 is total saturation. The RGB for red is 255 0 0, while blue is 0 0 255. Black has an RGB of 0 0 0, and white is 255 255 255. Any RGB where the values for red, green and blue are equal will be a shade of gray. Example: RGB 127 127 127.

If the user chooses a named, Liberty BASIC color, then chosen$ will contain both the red, green, blue values and the name. If the chosen color is not a named color, then the return will contain only the red, green and blue values:

color$="255 0 0"
colordialog color$, chosen$
print chosen$

'will print RGB and name for a named color

255 255 0 yellow

'will print RGB only for a non-named color:
250 230 190

The colordialog opens to the simple view, allowing the user to choose a color from one of the standard color boxes. The user can click the button "Define Custom Colors" to open the panel that provides access to all possible RGB combinations.

Here is a little demo to help you parse the returned string. The first word$() in the string will be the red value. The second word$() will be the green value and the third word$() will be the blue value. If there is a fourth word$(), it will be the Liberty BASIC named color.

color$="52 202 113"
colordialog color$, chosen$

print "Red is ";word$(chosen$,1)
print "Green is ";word$(chosen$,2)
print "Blue is ";word$(chosen$,3)

if word$(chosen$,4)<>"" then
    print "Name is ";word$(chosen$,4)
end if

If you are going to fill a graphicbox with the color chosen by the user, then check for the fourth word$(). If it exists, then the command will look like this:

print #1.gbox, "fill ";word$(chosen$,4)

If the user didn't choose a named color, then make a color out of the red, green and blue.

color$=word$(chosen$,1)+" "+word$(chosen$,2)+" "+word$(chosen$,3)

print #1.gbox, "fill ";color$


Home

Contest Update

Liberty BASIC 3!

Open Source Editor

Tip Corner

Callbacks Explained

Drag 'n' Drop

Drag 'n' Drop in LB3

Gnu Liberty BASIC Compiler

LB2BCX

Newsletter Help

Index