scrollbar.c - master - githubmirror/newt

scrollbar.c
139 строк3 KB
Robert Gill
improve handling of malloc failures
19 июн 2025, 09:48
19 июн 2025, 09:48d92e05d
#include <slang.h>
#include <stdlib.h>
#include <string.h>

#include "newt.h"
#include "newt_pr.h"

struct scrollbar {
    int curr;
    int cs, csThumb;
    int arrows;
} ;

static void sbDraw(newtComponent co);
static void sbDestroy(newtComponent co);
static void sbDrawThumb(newtComponent co, int isOn);

static struct componentOps sbOps = {
    sbDraw,
    newtDefaultEventHandler,
    sbDestroy,
    newtDefaultPlaceHandler,
    newtDefaultMappedHandler,
} ;

void newtScrollbarSet(newtComponent co, int where, int total) {
    struct scrollbar * sb = co->data;
    int new;

    if (sb->arrows)
	new = (where * (co->height - 3)) / (total ? total : 1) + 1;
    else
	new = (where * (co->height - 1)) / (total ? total : 1);
    if (new != sb->curr) {
	sbDrawThumb(co, 0);
	sb->curr = new;
	sbDrawThumb(co, 1);
    }
}

newtComponent newtVerticalScrollbar(int left, int top, int height,
				    int normalColorset, int thumbColorset) {
    newtComponent co;
    struct scrollbar * sb;

    co = malloc(sizeof(*co));
    if (co == NULL)
	return NULL;
    sb = malloc(sizeof(*sb));
    if (sb == NULL) {
	free(co);
	return NULL;
    }
    co->data = sb;
    co->destroyCallback = NULL;

    if (height >= 2) {
	sb->arrows = 1;
	sb->curr = 1;
    } else {
	sb->arrows = 0;
	sb->curr = 0;
    }
    sb->cs = normalColorset;
    sb->csThumb = thumbColorset;

    co->ops = &sbOps;
    co->isMapped = 0;
    co->left = left;
    co->top = top;
    co->height = height;
    co->width = 1;
    co->takesFocus = 0;  
    
    return co;
}

void newtScrollbarSetColors(newtComponent co, int normal, int thumb) {
    struct scrollbar * sb = co->data;

    sb->cs = normal;
    sb->csThumb = thumb;
    sbDraw(co);
}

static void sbDraw(newtComponent co) {
    struct scrollbar * sb = co->data;
    int i;

    if (!co->isMapped) return;

    SLsmg_set_color(sb->cs);

    SLsmg_set_char_set(1);
    if (sb->arrows) {
	newtGotorc(co->top, co->left);
	SLsmg_write_char(SLSMG_UARROW_CHAR);
	for (i = 1; i < co->height - 1; i++) {
	    newtGotorc(i + co->top, co->left);
	    SLsmg_write_char(SLSMG_CKBRD_CHAR);
	}
	newtGotorc(co->top + co->height - 1, co->left);
	SLsmg_write_char(SLSMG_DARROW_CHAR);
    } else {
	for (i = 0; i < co->height; i++) {
	    newtGotorc(i + co->top, co->left);
	    SLsmg_write_char(SLSMG_CKBRD_CHAR);
	}
    }

    SLsmg_set_char_set(0);

    sbDrawThumb(co, 1);
}

static void sbDrawThumb(newtComponent co, int isOn) {
    struct scrollbar * sb = co->data;
    SLtt_Char_Type ch = isOn ? SLSMG_BLOCK_CHAR : SLSMG_CKBRD_CHAR;

    if (!co->isMapped) return;

    newtGotorc(sb->curr + co->top, co->left);
    SLsmg_set_char_set(1);

    /*if (isOn)
	SLsmg_set_color(sb->csThumb);
    else*/
	SLsmg_set_color(sb->cs);

    SLsmg_write_char(ch);
    SLsmg_set_char_set(0);
}

static void sbDestroy(newtComponent co) {
    struct scrollbar * sb = co->data;
 
    free(sb);
    free(co);
}