richedit: Scrollinfo stored as 16-bit values externally. (Bug 19396) [try2]
Dylan Smith
dylan.ah.smith at gmail.com
Tue Jul 21 20:06:00 CDT 2009
[Prevented overflow by using int instead of WORD for pos in WM_VSCROLL]
The application Blitzin2 was sending WM_VSCROLL messages to the richedit
control directly, when normally this message is supposed to be a
notification sent after the scrollinfo is set. Native richedit controls
always use the 16-bit value passed to this message to set the scroll
position for SB_THUMBPOSITION, rather than trying to find a 32-bit value
through GetScrollInfo like I had previously done.
This brought up the question of how text with height greater than the
16-bit limit is handled. I ran some tests, and found that nMax is
capped at the maximum 16-bit value 0xffff, and nPos is scaled into this
range. This patch implements this behaviour, but keeps the precision
for the internal value, since it can be obtained through EM_POSFROMCHAR,
and is used for drawing the text.
EM_GETSCROLLPOS also uses this 16-bit value, and it must be derived from
an internal value since calling SetScrollInfo just before sending this
message didn't affect the returned value.
---
dlls/riched20/editor.c | 31 +++++++++++++------------------
dlls/riched20/paint.c | 20 ++++++++++++++++++--
2 files changed, 31 insertions(+), 20 deletions(-)
-------------- next part --------------
diff --git a/dlls/riched20/editor.c b/dlls/riched20/editor.c
index c3cd187..1e18c10 100644
--- a/dlls/riched20/editor.c
+++ b/dlls/riched20/editor.c
@@ -3587,6 +3587,11 @@ LRESULT ME_HandleMessage(ME_TextEditor *editor, UINT msg, WPARAM wParam,
POINT *point = (POINT *)lParam;
point->x = editor->horz_si.nPos;
point->y = editor->vert_si.nPos;
+ /* 16-bit scaled value is returned as stored in scrollinfo */
+ if (editor->horz_si.nMax > 0xffff)
+ point->x = MulDiv(point->x, 0xffff, editor->horz_si.nMax);
+ if (editor->vert_si.nMax > 0xffff)
+ point->y = MulDiv(point->y, 0xffff, editor->vert_si.nMax);
return 1;
}
case EM_GETTEXTRANGE:
@@ -4012,15 +4017,10 @@ LRESULT ME_HandleMessage(ME_TextEditor *editor, UINT msg, WPARAM wParam,
case SB_THUMBTRACK:
case SB_THUMBPOSITION:
{
- SCROLLINFO sbi;
- sbi.cbSize = sizeof(sbi);
- sbi.fMask = SIF_TRACKPOS;
- /* Try to get 32-bit track position value. */
- if (!GetScrollInfo(editor->hWnd, SB_HORZ, &sbi))
- /* GetScrollInfo failed, settle for 16-bit value in wParam. */
- sbi.nTrackPos = HIWORD(wParam);
-
- ME_HScrollAbs(editor, sbi.nTrackPos);
+ int pos = HIWORD(wParam);
+ if (editor->horz_si.nMax > 0xffff)
+ pos = MulDiv(pos, editor->horz_si.nMax, 0xffff);
+ ME_HScrollAbs(editor, pos);
break;
}
}
@@ -4064,15 +4064,10 @@ LRESULT ME_HandleMessage(ME_TextEditor *editor, UINT msg, WPARAM wParam,
case SB_THUMBTRACK:
case SB_THUMBPOSITION:
{
- SCROLLINFO sbi;
- sbi.cbSize = sizeof(sbi);
- sbi.fMask = SIF_TRACKPOS;
- /* Try to get 32-bit track position value. */
- if (!GetScrollInfo(editor->hWnd, SB_VERT, &sbi))
- /* GetScrollInfo failed, settle for 16-bit value in wParam. */
- sbi.nTrackPos = HIWORD(wParam);
-
- ME_VScrollAbs(editor, sbi.nTrackPos);
+ int pos = HIWORD(wParam);
+ if (editor->vert_si.nMax > 0xffff)
+ pos = MulDiv(pos, editor->vert_si.nMax, 0xffff);
+ ME_VScrollAbs(editor, pos);
break;
}
}
diff --git a/dlls/riched20/paint.c b/dlls/riched20/paint.c
index 4b5fed1..a5be178 100644
--- a/dlls/riched20/paint.c
+++ b/dlls/riched20/paint.c
@@ -1036,17 +1036,21 @@ void ME_ScrollAbs(ME_TextEditor *editor, int x, int y)
if (editor->horz_si.nPos != x) {
x = min(x, editor->horz_si.nMax);
x = max(x, editor->horz_si.nMin);
- ITextHost_TxSetScrollPos(editor->texthost, SB_HORZ, x, TRUE);
scrollX = editor->horz_si.nPos - x;
editor->horz_si.nPos = x;
+ if (editor->horz_si.nMax > 0xFFFF) /* scale to 16-bit value */
+ x = MulDiv(x, 0xFFFF, editor->horz_si.nMax);
+ ITextHost_TxSetScrollPos(editor->texthost, SB_HORZ, x, TRUE);
}
if (editor->vert_si.nPos != y) {
y = min(y, editor->vert_si.nMax - (int)editor->vert_si.nPage);
y = max(y, editor->vert_si.nMin);
- ITextHost_TxSetScrollPos(editor->texthost, SB_VERT, y, TRUE);
scrollY = editor->vert_si.nPos - y;
editor->vert_si.nPos = y;
+ if (editor->vert_si.nMax > 0xFFFF) /* scale to 16-bit value */
+ y = MulDiv(y, 0xFFFF, editor->vert_si.nMax);
+ ITextHost_TxSetScrollPos(editor->texthost, SB_VERT, y, TRUE);
}
if (abs(scrollX) > editor->sizeWindow.cx ||
@@ -1170,6 +1174,12 @@ void ME_UpdateScrollBar(ME_TextEditor *editor)
if ((bScrollBarWillBeVisible || bScrollBarWasVisible) &&
editor->styleFlags & WS_HSCROLL)
{
+ if (si.nMax > 0xFFFF)
+ {
+ /* Native scales the scrollbar info to 16-bit external values. */
+ si.nPos = MulDiv(si.nPos, 0xFFFF, si.nMax);
+ si.nMax = 0xFFFF;
+ }
if (editor->hWnd) {
SetScrollInfo(editor->hWnd, SB_HORZ, &si, TRUE);
} else {
@@ -1219,6 +1229,12 @@ void ME_UpdateScrollBar(ME_TextEditor *editor)
if ((bScrollBarWillBeVisible || bScrollBarWasVisible) &&
editor->styleFlags & WS_VSCROLL)
{
+ if (si.nMax > 0xFFFF)
+ {
+ /* Native scales the scrollbar info to 16-bit external values. */
+ si.nPos = MulDiv(si.nPos, 0xFFFF, si.nMax);
+ si.nMax = 0xFFFF;
+ }
if (editor->hWnd) {
SetScrollInfo(editor->hWnd, SB_VERT, &si, TRUE);
} else {
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