Fix for bug [1739605] - [text see] misbehaves following widget create/populate - Patch from Koen Danckaert

2 files changed, 20 insertions, 0 deletions

diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index 74620fc..86a81c0 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -5239,6 +5239,15 @@ TkTextSetYView(
     }
 
     /*
+     * If the window height is smaller than the line height, prefer to make
+     * the top of the line visible.
+     */
+
+    if (dInfoPtr->maxY - dInfoPtr->y < lineHeight) {
+        bottomY = lineHeight;
+    }
+
+    /*
      * Our job now is to arrange the display so that indexPtr appears as low
      * on the screen as possible but with its bottom no lower than bottomY.
      * BottomY is the bottom of the window if the desired line is just below
diff --git a/tests/textDisp.test b/tests/textDisp.test
index 5508d7c..038eccd 100644
--- a/tests/textDisp.test
+++ b/tests/textDisp.test
@@ -1574,6 +1574,17 @@ test textDisp-11.20 {TkTextSetYView, see in elided lines} {
     # this shall not crash (null chunkPtr in TkTextSeeCmd is tested)
     .top.t see 3.0
 } {}
+test textDisp-11.21 {TkTextSetYView, window height smaller than the line height} {
+    .top.t delete 1.0 end
+    for {set i 1} {$i <= 10} {incr i} {
+        .top.t insert end "Line $i\n"
+    }
+    set lineheight [font metrics [.top.t cget -font] -linespace]
+    wm geometry .top 200x[expr {$lineheight / 2}]
+    update
+    .top.t see 1.0
+    .top.t index @0,[expr {$lineheight - 2}]
+} {1.0}
 
 .t configure -wrap word
 .t delete 50.0 51.0