The Graphics Panel
The GRAPHICS panel contains properties that are relevant to graphics and mouse, like the sizem, the wrapping mode, or the mouse position.
BGCOLOR
Part of: GRAPHICS
Controls the background color of the Graphics panel.
Syntax
GPROP "GRAPHICS "BGCOLOR
PPROP "GRAPHICS "BGCOLOR color
Description
BGCOLOR controls the background color of the Graphics panel. Initially, this color is transparent so background images can shine through. Try to set the background color’s opacity value together with a background image!
SETBG sets this property.
Examples
GPROP “GRAPHICS “BGCOLOR Result: [255 255 255 0] PPROP “GRAPHICS “BGCOLOR [255 0 0 0.5]
BGPATTERN
Part of: GRAPHICS
Controls the background pattern.
Syntax
GPROP "GRAPHICS "BGPATTERN
PPROP "GRAPHICS "BGPATTERN pattern
Description
BGPATTERN controls the background pattern using the current background color. Please see the SETBGPATTERN command for a list of possible input values.
Examples
GPROP “GRAPHICS “BGPATTERN Result: 0
BUTTON
Part of: GRAPHICS
Reports the state of the mouse’s buttons.
Syntax
GPROP "GRAPHICS "BUTTON
WHEN "GRAPHICS [BUTTON = 1] [PR [LEFT MOUSE BUTTON CLICKED]]
Description
BUTTON reports the state of the mouse buttons. The property is read-only. You can monitor the state of the buttons with the WHEN command.
The value of the BUTTON property is 1 for the left button down, 2 for the right button down, and 4 for the middle button down. All of these values can be combined if more than one button is pressed. If the mouse supports more than three buttons, more values like 8, 16, or 32 are possible.
Examples
GPROP “GRAPHICS “BUTTON Result: 0
FROZEN
Part of: GRAPHICS
Reports TRUE if the graphics are frozen.
Syntax
GPROP "GRAPHICS "FROZEN
Description
Reports TRUE if the Graphics panel is frozen. A frozen panel does not update while drawing to prevent unneccessary flicker. The FREEZEPIC and UNFREEZEPIC commands handle this property.
Examples
GPROP “GRAPHICS “FROZEN Result: FALSE
MOUSE
Part of: GRAPHICS
Reports the position of the mouse.
Syntax
GPROP "GRAPHICS "MOUSE
Description
Reports the position of the mouse over the Graphics panel as a two-element list of turtle coordinates. The property is read-only. You can monitor the mouse position with the WHEN command.
Examples
GPROP “GRAPHICS “MOUSE Result: [102 -35]
OFFSET
Part of: GRAPHICS
Controls the location of the Graphics panel’s center point.
Syntax
GPROP "GRAPHICS "OFFSET
Description
This property controls the offset of the entire Graphics panel from the original center point. Setting the offset’s first element to, for example, 100, moves all content of the Graphics panel 100 pixels to the right. If you provide a single input (a number) as input, it sets the offset to that value in both directions.
Note: Due to a bug in Logo, the value for the vertical offset is inverted. A positive value moves the origin down, not up.
Examples
GPROP “GRAPHICS “OFFSET Result: [0 0]
SIZE
Part of: GRAPHICS
Reports the size of the Graphics panel.
Syntax
GPROP "GRAPHICS "SIZE
Description
SIZE reports the size of the Graphics panel in pixels. The property is read-only. You can monitor any changes of the panel size with the WHEN command.
Examples
GPROP “GRAPHICS “SIZE Result: [1032 899]
TOUCH
Part of: GRAPHICS
Reports touch data on touch screen equipped devices.
Syntax
GPROP "GRAPHICS "TOUCH
Description
TOUCH reports a list of lists when one or more fingers touch the surface of the Graphics panel. Each list element stands for a finger. Each “finger list” has three elements. The first element is a two-element list of the X and Y coordinates. The next element is again a two-element list of the touch area’s width and height; a finger is never so small that it touches only a single pixel as a mouse does. Finally, the third element indicates the amount of pressure that the finger applied; this is a value between 0 and 1. For touch screens without pressure sensitivity (most are not pressure sensitive), the value is 1.
The property is read-only. You can monitor the touch data with the WHEN command.
Examples
GPROP “GRAPHICS “TOUCH Result: []
VISIBLE
Part of: GRAPHICS
Reports the panel’s visibility
Syntax
GPROP "GRAPHICS "VISIBLE
Description
The VISIBLE property reports TRUE if the panel is part of the current view. If the panel is invisible because it is not part of the current view, it reports FALSE. The property is read-only.
Examples
GPROP “GRAPHICS “VISIBLE Result: TRUE
WRAPMODE
Part of: GRAPHICS
Controls how a widget reacts when it hits the edge of the Graphics panel
Syntax
GPROP "GRAPHICS "WRAPMODE
PPROP "GRAPHICS "WRAPMODE mode
Description
WRAPMODE controls wrap mode for all widgets (turtles, bitmaps etc.); one of WRAP, FENCE, WINDOW, or BOUNCE. Wrap modes can be set for individual widgets by setting their own WRAPMODE property.
See the WRAP, FENCE, WINDOW and BOUNCE commands for more details.
Examples
GPROP “GRAPHICS “WRAPMODE Result: WRAP