From 388100bece4ccadd2e908108a4f1de2733a7ad25 Mon Sep 17 00:00:00 2001
From: vincentdarley <vincentdarley>
Date: Mon, 10 Nov 2003 14:37:33 +0000
Subject: handling of zero-pixel text widgets
---
ChangeLog | 5 ++
generic/tkTextDisp.c | 140 +++++++++++++++++++++++++++------------------------
2 files changed, 79 insertions(+), 66 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index ac26fbc..64aa717 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2003-11-10 Vince Darley <vincentdarley@users.sourceforge.net>
+
+ * generic/tkTextDisp.c: correct yview handling of text widgets
+ containing no vertical pixels at all.
+
2003-11-08 Pat Thoyts <patthoyts@users.sourceforge.net>
* win/tclWinSend.c: Fixed an error returning the registered name.
diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index 85a160d..ee1e40b 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -13,7 +13,7 @@
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tkTextDisp.c,v 1.25 2003/11/08 17:22:46 vincentdarley Exp $
+ * RCS: @(#) $Id: tkTextDisp.c,v 1.26 2003/11/10 14:37:33 vincentdarley Exp $
*/
#include "tkPort.h"
@@ -5352,76 +5352,84 @@ GetYView(interp, textPtr, report)
totalPixels = TkBTreeNumPixels(textPtr->tree);
- /*
- * Get the pixel count for the first display visible pixel of the
- * first visible line. If the first visible line is only partially
- * visible, then we use 'topPixelOffset' to get the difference.
- */
- count = GetPixelCount(textPtr, dlPtr);
- first = ((double) (count + dInfoPtr->topPixelOffset))/((double)totalPixels);
-
- /*
- * Add on the total number of visible pixels to get the count to
- * the last visible pixel.
- */
- while (1) {
- int extra;
- count += dlPtr->height;
+ if (totalPixels == 0) {
+ first = 0.0;
+ last = 1.0;
+ } else {
+ /*
+ * Get the pixel count for the first display visible pixel of the
+ * first visible line. If the first visible line is only
+ * partially visible, then we use 'topPixelOffset' to get the
+ * difference.
+ */
+ count = GetPixelCount(textPtr, dlPtr);
+ first = ((double) (count + dInfoPtr->topPixelOffset))
+ /((double)totalPixels);
- extra = dlPtr->y + dlPtr->height - dInfoPtr->maxY;
- if (extra > 0) {
- /*
- * This much of the last line is not visible, so don't
- * count these pixels. Since we've reached the bottom
- * of the window, we break out of the loop.
- */
- count -= extra;
- break;
- }
- if (dlPtr->nextPtr == NULL) {
- break;
- }
- dlPtr = dlPtr->nextPtr;
- }
-
- if (count > totalPixels) {
/*
- * It can be possible, if we do not update each line's
- * pixelHeight cache when we lay out individual DLines that
- * the count generated here is more up-to-date than that
- * maintained by the BTree. In such a case, the best we can
- * do here is to fix up 'count' and continue, which might
- * result in small, temporary perturbations to the size of
- * the scrollbar. This is basically harmless, but in a
- * perfect world we would not have this problem.
- *
- * For debugging purposes, if anyone wishes to improve the text
- * widget further, the following 'panic' can be activated. In
- * principle it should be possible to ensure the BTree is always
- * at least as up to date as the display, so in the future we
- * might be able to leave the 'panic' in permanently when we
- * believe we have resolved the cache synchronisation issue.
- *
- * However, to achieve that goal would, I think, require a
- * fairly substantial refactorisation of the code in this
- * file so that there is much more obvious and explicit
- * coordination between calls to LayoutDLine and updating
- * of each TkTextLine's pixelHeight. The complicated bit
- * is that LayoutDLine deals with individual display lines,
- * but pixelHeight is for a logical line.
+ * Add on the total number of visible pixels to get the count to
+ * the last visible pixel.
*/
-#if 0
- char buffer[200];
+ while (1) {
+ int extra;
+ count += dlPtr->height;
- sprintf(buffer,
- "Counted more pixels (%d) than expected (%d) total pixels in text widget scroll bar calculation.",
- count, totalPixels);
- panic(buffer);
-#endif
- count = totalPixels;
+ extra = dlPtr->y + dlPtr->height - dInfoPtr->maxY;
+ if (extra > 0) {
+ /*
+ * This much of the last line is not visible, so don't
+ * count these pixels. Since we've reached the bottom
+ * of the window, we break out of the loop.
+ */
+ count -= extra;
+ break;
+ }
+ if (dlPtr->nextPtr == NULL) {
+ break;
+ }
+ dlPtr = dlPtr->nextPtr;
+ }
+
+ if (count > totalPixels) {
+ /*
+ * It can be possible, if we do not update each line's
+ * pixelHeight cache when we lay out individual DLines that
+ * the count generated here is more up-to-date than that
+ * maintained by the BTree. In such a case, the best we can
+ * do here is to fix up 'count' and continue, which might
+ * result in small, temporary perturbations to the size of
+ * the scrollbar. This is basically harmless, but in a
+ * perfect world we would not have this problem.
+ *
+ * For debugging purposes, if anyone wishes to improve the
+ * text widget further, the following 'panic' can be
+ * activated. In principle it should be possible to ensure
+ * the BTree is always at least as up to date as the display,
+ * so in the future we might be able to leave the 'panic' in
+ * permanently when we believe we have resolved the cache
+ * synchronisation issue.
+ *
+ * However, to achieve that goal would, I think, require a
+ * fairly substantial refactorisation of the code in this
+ * file so that there is much more obvious and explicit
+ * coordination between calls to LayoutDLine and updating of
+ * each TkTextLine's pixelHeight. The complicated bit is
+ * that LayoutDLine deals with individual display lines, but
+ * pixelHeight is for a logical line.
+ */
+ #if 0
+ char buffer[200];
+
+ sprintf(buffer,
+ "Counted more pixels (%d) than expected (%d) total pixels in text widget scroll bar calculation.",
+ count, totalPixels);
+ panic(buffer);
+ #endif
+ count = totalPixels;
+ }
+
+ last = ((double) (count))/((double)totalPixels);
}
-
- last = ((double) (count))/((double)totalPixels);
if (!report) {
listObj = Tcl_NewListObj(0,NULL);
--
cgit v0.12