Gamma/Photon : Using Gamma™ with the Photon microGUI®, Version 1.1
	Widget Classes

`PtBkgd`

PtBkgd — A background image, bitmap, or color-gradient.

Synopsis

class PtBkgd PtPane
{
    bkgd_brt_from;       // unsigned short  (Pt_ARG_BKGD_BRT_FROM)    
    bkgd_brt_to;         // unsigned short  (Pt_ARG_BKGD_BRT_TO)    
    bkgd_hue_from;       // unsigned short  (Pt_ARG_BKGD_HUE_FROM)    
    bkgd_hue_to;         // unsigned short  (Pt_ARG_BKGD_HUE_TO)    
    bkgd_image;          // PhImage  (Pt_ARG_BKGD_IMAGE)    
    bkgd_mix;            // unsigned short  (Pt_ARG_BKGD_MIX)    
    bkgd_orientation;    // unsigned short  (Pt_ARG_BKGD_ORIENTATION)    
    bkgd_pix_height;     // unsigned short  (Pt_ARG_BKGD_PIX_HEIGHT)    
    bkgd_pix_width;      // unsigned short  (Pt_ARG_BKGD_PIX_WIDTH)    
    bkgd_pixcolors;      // color array  (Pt_ARG_BKGD_PIXCOLORS)    
    bkgd_pixmap;         // char array array  (Pt_ARG_BKGD_PIXMAP)    
    bkgd_sat_from;       // unsigned short  (Pt_ARG_BKGD_SAT_FROM)    
    bkgd_sat_to;         // unsigned short  (Pt_ARG_BKGD_SAT_TO)    
    bkgd_spacing;        // PhPoint  (Pt_ARG_BKGD_SPACING)    
    bkgd_steps;          // unsigned short  (Pt_ARG_BKGD_STEPS)    
    bkgd_tile;           // unsigned short  (Pt_ARG_BKGD_TILE)    
    bkgd_type;           // unsigned short  (Pt_ARG_BKGD_TYPE)    
}

Base Classes

PtWidget <-- PtBasic <-- PtContainer <-- PtPane <-- PtBkgd

Description

This widget lets you make backgrounds for application windows. The bkgd_type variable lets you choose from three types of backgrounds: images, pixmaps, and color-gradients, which are controlled with their associated variables.

Images can be created in graphics programs, loaded with a call to PxLoadImage, and subsequently used for background images as instances of PhImage. They can be tiled in several ways using the bkgd_tile and bkgd_spacing variables.

Pixmaps are bitmapped images created in PhAB, or by using the Photon function PtDrawBitmap. This type of image can easily be made transparent.

Color gradients are specified by their hue, saturation, and brightness variables: bkgd_hue, bkgd_sat and bkgd_brt, each with a _from and _to variable for specifying the range. But the range can only be applied to one of the three. Choose one of them, and set the flag for it in the bkgd_type variable. Then for that one alone you can specify the range, assigning both its _from and _to variables. The other two take only the _to variable.

Other options for color gradients include horizontal or vertical orientation, color dithering, and number of gradient steps.

For detailed information, please refer to PtBkgd in the Photon documentation.

Instance Variables

bkgd_brt_from, bkgd_brt_to

An integer between 0 and 255 specifying the brightness range (black to full brightness) of color gradients, using the hue/saturation/brightness color model.

bkgd_hue_from, bkgd_hue_to

An integer between 0 and 65535 specifying the hue range (on the color spectrum) of color gradients, using the hue/saturation/brightness color model.

bkgd_image

A PhImage that you wish to display.

bkgd_mix

An integer that specifies whether or not dithering is used in color-gradient backgrounds. 1 (the default) is on, 0 is off.

bkgd_orientation

A constant specifying the orientation of color-gradient backgrounds. The default is vertical.

This instance variable may have one of the following values:

Constant	Description
`Pt_BKGD_HORIZONTAL`	Sets the gradient orientation to horizontal.
`Pt_BKGD_VERTICAL`	Sets the gradient orientation to vertical.

bkgd_pix_height, bkgd_pix_width

A number of pixels specifying the height and width of a pixmap image.

bkgd_pixcolors

An array of colors used by a pixmap image.

bkgd_pixmap

A bitmapped background image created in PhAB. This type of image can be easily made transparent.

bkgd_sat_from, bkgd_sat_to

An integer between 0 and 255 specifying the saturation range (white to full color) of color gradients, using the hue/saturation/brightness color model.

bkgd_spacing

A PhPoint whose x and y values specify the horizontal and vertical separation between tiles. Default is:

{PhPoint (x	. 0) (y . 0)}

bkgd_steps

An integer specifying the number of steps to get from the minimum gradient value to the maximum. Default is 10.

bkgd_tile

A constant specifying the tiling option for images and pixmaps.

This instance variable may have one of the following values:

Constant	Description
`Pt_BKGD_NONE`	None.
`Pt_BKGD_GRID`	The image repeats in rows and columns.
`Pt_BKGD_ALT`	The image repeats alternately, like brickwork.
`Pt_BKGD_CENTER`	The image is drawn in the center of the container.
`Pt_BKGD_CENTER_GRID`	The image is drawn in the center, and repeated for a single row and column around the border.

bkgd_type

A constant specifying the type of background image you want to use. The relevance of other variables depends on this choice.

This instance variable may have one of the following values:

Constant	Description
`Pt_BKGD_HUE`	The background color gradient is based on hue value.
`Pt_BKGD_SATURATION`	The background color gradient is based on saturation value.
`Pt_BKGD_BRIGHTNESS`	The default, the background color gradient is based on brightness value.
`Pt_BKGD_PIXMAP`	Used to create a background of a small/hand-drawn image; background fill color stays visible.
`Pt_BKGD_IMAGE`	Used to create a background with an imported image.

Example

This example, ex_PtBkgd.g, is included in the product distribution.

#!/usr/cogent/bin/phgamma

/*
 * This example demonstrates a saturation color_gradient
 * PtBkgd anchored to a window.
 */

require_lisp("PhotonWidgets.lsp");
PtInit(nil);

win = new(PtWindow);
win.SetDim (300,300);

back = new(PtBkgd);
back.bkgd_type = Pt_BKGD_SATURATION;
back.bkgd_brt_to = 255;
back.bkgd_hue_to = 30000;
back.bkgd_sat_from = 255;
back.bkgd_sat_to = 0;
back.bkgd_steps = 200;
back.SetDim(300,300);
back.bkgd_orientation = Pt_BKGD_HORIZONTAL;
back.anchor_flags = Pt_LEFT_ANCHORED_RELATIVE |
                    Pt_RIGHT_ANCHORED_RELATIVE |
		    Pt_TOP_ANCHORED_RELATIVE |
		    Pt_BOTTOM_ANCHORED_RELATIVE;

PtRealizeWidget(win);
PtMainLoop();


PtBitmap		PtButton