From 5c72fb03023c4e2c5626c16c21de0c0c6fb35f43 Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue, 21 Jun 2011 19:58:33 +0200
Subject: [PATCH] fix form scrolling

The previous commit breaks form scrolling. Instead of keeping a copy of
all components' coordinates, move all components when the form is
scrolled and use their real coordinates adjusted by vertical offset to
get the coordinates and size of the form.
---
 form.c | 74 +++++++++++++++++++++++++++++++---------------------------
 1 file changed, 39 insertions(+), 35 deletions(-)

diff --git a/form.c b/form.c
index 8e81485..4b5f850 100644
--- a/form.c
+++ b/form.c
@@ -373,8 +373,7 @@ static int Gpm_GetEvent(Gpm_Event *event)
 *****************************************************************************/
 
 struct element {
-    int top, left;		/* Actual, not virtual. These are translated */
-    newtComponent co;		/* into actual through vertOffset */
+    newtComponent co;
 };
 
 struct fdInfo {
@@ -428,9 +427,10 @@ static inline int componentFits(newtComponent co, int compNum) {
     struct form * form = co->data;
     struct element * el = form->elements + compNum;
 
-    if ((co->top + form->vertOffset) > el->top) return 0;
-    if ((co->top + form->vertOffset + co->height) <
-	    (el->top + el->co->height)) return 0;
+    if (co->top > el->co->top)
+	return 0;
+    if (co->top + co->height < el->co->top + el->co->height)
+	return 0;
 
     return 1;
 }
@@ -492,6 +492,26 @@ newtComponent newtFormGetCurrent(newtComponent co) {
     return form->elements[form->currComp].co;
 }
 
+static void formScroll(newtComponent co, int delta) {
+    struct form * form = co->data;
+    struct element * el;
+    int i, newVertOffset = form->vertOffset + delta;
+
+    if (newVertOffset < 0)
+	newVertOffset = 0;
+    if (newVertOffset > form->numRows - co->height)
+	newVertOffset = form->numRows - co->height;
+
+    delta = newVertOffset - form->vertOffset;
+    form->vertOffset = newVertOffset;
+
+    for (i = 0, el = form->elements; i < form->numComps; i++, el++) {
+	if (el->co == form->vertBar)
+	    continue;
+	el->co->ops->place(el->co, el->co->left, el->co->top - delta);
+    }
+}
+
 void newtFormSetCurrent(newtComponent co, newtComponent subco) {
     struct form * form = co->data;
     int i, new;
@@ -505,9 +525,7 @@ void newtFormSetCurrent(newtComponent co, newtComponent subco) {
 
     if (co->isMapped && !componentFits(co, new)) {
 	gotoComponent(form, -1);
-	form->vertOffset = form->elements[new].top - co->top - 1;
-	if (form->vertOffset > (form->numRows - co->height))
-	    form->vertOffset = form->numRows - co->height;
+	formScroll(co, form->elements[new].co->top - co->top - 1);
     }
 
     gotoComponent(form, new);
@@ -543,9 +561,6 @@ void newtFormAddComponent(newtComponent co, newtComponent newco) {
 			    sizeof(*(form->elements)) * form->numCompsAlloced);
     }
 
-    /* we grab real values for these a bit later */
-    form->elements[form->numComps].left = -2;
-    form->elements[form->numComps].top = -2;
     form->elements[form->numComps].co = newco;
 
     if (newco->takesFocus && form->currComp == -1)
@@ -572,17 +587,14 @@ static void formPlace(newtComponent co, int left, int top) {
     struct element * el;
     int i;
 
-    newtFormSetSize(co);
-
     vertDelta = top - co->top;
     horizDelta = left - co->left;
     co->top = top;
     co->left = left;
 
     for (i = 0, el = form->elements; i < form->numComps; i++, el++) {
-	el->top += vertDelta;
-	el->left += horizDelta;
-	el->co->ops->place(el->co, el->co->left, el->co->top);
+	el->co->ops->place(el->co, el->co->left + horizDelta,
+		el->co->top + vertDelta);
     }
 }
 
@@ -597,19 +609,13 @@ void newtDrawForm(newtComponent co) {
     newtClearBox(co->left, co->top, co->width, co->height);
 
     for (i = 0, el = form->elements; i < form->numComps; i++, el++) {
-	/* the scrollbar *always* fits somewhere */
-	if (el->co == form->vertBar) {
+	/* only draw it if it'll fit on the screen vertically
+	   (the scrollbar *always* fits somewhere) */
+	if (el->co == form->vertBar || componentFits(co, i)) {
 	    el->co->ops->mapped(el->co, 1);
 	    el->co->ops->draw(el->co);
 	} else {
-	    /* only draw it if it'll fit on the screen vertically */
-	    if (componentFits(co, i)) {
-		el->co->ops->place(el->co, el->left, el->top - form->vertOffset);
-		el->co->ops->mapped(el->co, 1);
-		el->co->ops->draw(el->co);
-	    } else {
-		el->co->ops->mapped(el->co, 0);
-	    }
+	    el->co->ops->mapped(el->co, 0);
 	}
     }
 
@@ -764,22 +770,21 @@ static struct eventResult formEvent(newtComponent co, struct event ev) {
 
 	/* make sure this component is visible */
 	if (!componentFits(co, new)) {
+	    int vertDelta;
+
 	    gotoComponent(form, -1);
 
 	    if (dir < 0) {
 		/* make the new component the first one */
-		form->vertOffset = form->elements[new].top - co->top;
+		vertDelta = form->elements[new].co->top - co->top;
 	    } else {
 		/* make the new component the last one */
-		form->vertOffset = (form->elements[new].top +
+		vertDelta = (form->elements[new].co->top +
 					form->elements[new].co->height) -
 				    (co->top + co->height);
 	    }
 
-	    if (form->vertOffset < 0) form->vertOffset = 0;
-	    if (form->vertOffset > (form->numRows - co->height))
-		form->vertOffset = form->numRows - co->height;
-
+	    formScroll(co, vertDelta);
 	    newtDrawForm(co);
 	}
 
@@ -880,9 +885,6 @@ void newtFormSetSize(newtComponent co) {
 	    first = 0;
 	}
 
- 	el->left = el->co->left;
- 	el->top = el->co->top;
-
 	if (co->left > el->co->left) {
 	    delta = co->left - el->co->left;
 	    co->left -= delta;
@@ -909,6 +911,8 @@ void newtFormSetSize(newtComponent co) {
 	    form->numRows = el->co->top + el->co->height - co->top;
 	}
     }
+
+    co->top += form->vertOffset;
 }
 
 void newtFormRun(newtComponent co, struct newtExitStruct * es) {
-- 
2.47.2