shithub: vdiff

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implement panning (thanks qwx)

	allow panning with left/right arrows instead of forcing
	user to resize window

--- a/vdiff.c

+++ b/vdiff.c

@@ -50,6 +50,8 @@

 Line **lines;

 int lsize;

 int lcount;

+int maxlength;

+int Δpan;

 const char ellipsis[] = "...";

 void

@@ -59,19 +61,23 @@

 	Point p;

 	Rune  rn;

 	char *s;

+	int off;

 	bg = cols[l->t];

 	draw(screen, r, bg, nil, ZP);

 	p = Pt(r.min.x + Hpadding, r.min.y + (Dy(r)-font->height)/2);

-	for(s = l->s; *s; s++){

-		if(*s == '\t')

+	off = Δpan / stringwidth(font, " ");

+	for(s = l->s; *s; off--){

+		if(*s == '\t'){

 			p = string(screen, p, fg, ZP, font, "    ");

-		else if((p.x+Hpadding+stringwidth(font, " ")+stringwidth(font, ellipsis)>=textr.max.x)){

+			s++;

+		}else if((p.x+Hpadding+stringwidth(font, " ")+stringwidth(font, ellipsis)>=textr.max.x)){

 			string(screen, p, fg, ZP, font, ellipsis);

 			break;

 		}else{

-			s += chartorune(&rn, s) - 1;

-			p = runestringn(screen, p, fg, ZP, font, &rn, 1);

+			s += chartorune(&rn, s);

+			if(off <= 0)

+				p = runestringn(screen, p, fg, ZP, font, &rn, 1);

 		}

 	}

 }

@@ -98,6 +104,20 @@

 }

 void

+pan(int off)

+{

+	int max;

+

+	max = Hpadding + maxlength * stringwidth(font, " ") + 2 * stringwidth(font, ellipsis) - Dx(textr);

+	Δpan += off * stringwidth(font, " ");

+	if(Δpan < 0 || max <= 0)

+		Δpan = 0;

+	else if(Δpan > max)

+		Δpan = max;

+	redraw();

+}

+

+void

 scroll(int off)

 {

 	if(off<0 && offset<=0)

@@ -184,6 +204,7 @@

 parseline(char *f, int n, char *s)

 {

 	Line *l;

+	int len;

 	l = malloc(sizeof *l);

 	if(l==nil)

@@ -195,6 +216,9 @@

 		l->f = f;

 	else

 		l->f = nil;

+	len = strlen(s);

+	if(len > maxlength)

+		maxlength = len;

 	return l;

 }

@@ -347,6 +371,12 @@

 				break;

 			case Kdown:

 				scroll(1);

+				break;

+			case Kleft:

+				pan(-4);

+				break;

+			case Kright:

+				pan(4);

 				break;

 			}

 			break;