c:graphics.h:setbkcolor
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c:graphics.h:setbkcolor [2015/05/06 23:06] |
c:graphics.h:setbkcolor [2024/02/16 01:05] (current) |
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| + | ===== setbkcolor ===== | ||
| + | |||
| + | |||
| + | ====Syntax of setbkcolor ==== | ||
| + | <code c> | ||
| + | #include <graphics.h> | ||
| + | void setbkcolor(int color); | ||
| + | </code> | ||
| + | |||
| + | |||
| + | ==== Description of setbkcolor ==== | ||
| + | <code c> | ||
| + | setbkcolor sets the background to the color specified by color. The | ||
| + | argument color can be a name or a number as listed below. (These symbolic | ||
| + | names are defined in graphics.h.) | ||
| + | Name Value | ||
| + | BLACK 0 | ||
| + | BLUE 1 | ||
| + | GREEN 2 | ||
| + | CYAN 3 | ||
| + | RED 4 | ||
| + | MAGENTA5 | ||
| + | BROWN 6 | ||
| + | LIGHTGRAY 7 | ||
| + | DARKGRAY 8 | ||
| + | LIGHTBLUE 9 | ||
| + | LIGHTGREEN 10 | ||
| + | LIGHTCYAN 11 | ||
| + | LIGHTRED 12 | ||
| + | LIGHTMAGENTA 13 | ||
| + | YELLOW 14 | ||
| + | WHITE 15 | ||
| + | For example, if you want to set the background color to blue, you can | ||
| + | call | ||
| + | setbkcolor(BLUE) /* or */ setbkcolor(1) | ||
| + | On CGA and EGA systems, setbkcolor changes the background color by | ||
| + | changing the first entry in the palette. | ||
| + | If you use an EGA or a VGA, and you change the palette colors with | ||
| + | setpalette or setallpalette, the defined symbolic constants might not | ||
| + | give you the correct color. This is because the parameter to setbkcolor | ||
| + | indicates the entry number in the current palette rather than a specific | ||
| + | color (unless the parameter passed is 0, which always sets the background | ||
| + | color to black). | ||
| + | </code> | ||
| + | |||
| + | |||
| + | ==== Example of setbkcolor ==== | ||
| + | <code c> | ||
| + | /* setbkcolor example */ | ||
| + | |||
| + | #include <graphics.h> | ||
| + | #include <stdlib.h> | ||
| + | #include <stdio.h> | ||
| + | #include <conio.h> | ||
| + | |||
| + | int main(void) | ||
| + | { | ||
| + | /* _select driver and mode that supports multiple background colors*/ | ||
| + | int gdriver = EGA, gmode = EGAHI, errorcode; | ||
| + | int bkcol, maxcolor, x, y; | ||
| + | char msg[80]; | ||
| + | |||
| + | /* initialize graphics and local variables */ | ||
| + | initgraph(&gdriver, &gmode, ""); | ||
| + | |||
| + | /* read result of initialization */ | ||
| + | errorcode = graphresult(); | ||
| + | if (errorcode != grOk) { /* an error occurred */ | ||
| + | |||
| + | printf("Graphics error: %s\n", grapherrormsg(errorcode)); | ||
| + | printf("Press any key to halt:"); | ||
| + | getch(); | ||
| + | exit(1); /* terminate with an error code */ | ||
| + | } | ||
| + | |||
| + | /* maximum color index supported */ | ||
| + | maxcolor = getmaxcolor(); | ||
| + | |||
| + | /* for centering text messages */ | ||
| + | settextjustify(CENTER_TEXT, CENTER_TEXT); | ||
| + | x = getmaxx() / 2; | ||
| + | y = getmaxy() / 2; | ||
| + | |||
| + | /* loop through the available colors */ | ||
| + | for (bkcol=0; bkcol<=maxcolor; bkcol++) { | ||
| + | |||
| + | |||
| + | /* clear the screen */ | ||
| + | cleardevice(); | ||
| + | |||
| + | /* select a new background color */ | ||
| + | setbkcolor(bkcol); | ||
| + | |||
| + | /* output a messsage */ | ||
| + | if (bkcol == WHITE) | ||
| + | setcolor(EGA_BLUE); | ||
| + | sprintf(msg, "Background color: %d", bkcol); | ||
| + | outtextxy(x, y, msg); | ||
| + | getch(); | ||
| + | } | ||
| + | |||
| + | /* clean up */ | ||
| + | closegraph(); | ||
| + | return 0; | ||
| + | } | ||
| + | </code> | ||
| + | |||
| + | |||
| + | ==== See also ==== | ||
| + | [[getbkcolor]] | ||
| + | [[setallpalette]] | ||
| + | [[setcolor]] | ||
| + | [[setpalette]] | ||
| + | |||
| + | |||
| + | ===== output of setbkcolor example ===== | ||
| + | |||
| + | no output of example at the moment | ||
| + | do not hesitate and add it... | ||
| + | |||
| + | |||
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