Take terminal width and auto-wrapping into account

... when doing "repaint the active block" calculations. Bug #34
varabyte · Sep 13, 2021 · b69ffdc · b69ffdc
1 parent e9b2a23
commit b69ffdc
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Showing 3 changed files with 18 additions and 2 deletions.
diff --git a/konsole/src/main/kotlin/com/varabyte/konsole/runtime/KonsoleBlock.kt b/konsole/src/main/kotlin/com/varabyte/konsole/runtime/KonsoleBlock.kt
@@ -101,12 +101,24 @@ class KonsoleBlock internal constructor(val app: KonsoleApp, private val block:
 
             val clearBlockCommand = buildString {
                 if (!renderer.textArea.isEmpty()) {
+                    // Note: Terminals auto-wrap lines, which is nice for the user but screws up our "erase the lines"
+                    // calculations. We make a best effort to figure out where extra newlines would be added, here,
+                    // although note that if the user keeps resizing their terminal while our app is running, it seems
+                    // like the width value we get doesn't update. See also: bug #34
+                    val extraNumLines = renderer.textArea.toRawText()
+                        .split("\n")
+                        // The line gets an implicit newline once it goes ONE over the terminal width - or in other
+                        // words, a 20 character line fits perfectly in a 20 column terminal, so don't treat that case
+                        // as an extra newline
+                        .sumOf { line -> (line.length - 1) / app.terminal.width }
+                    val totalNumLines = renderer.textArea.numLines + extraNumLines
+
                     // To clear an existing block of 'n' lines, completely delete all but one of them, and then delete the
                     // last one down to the beginning (in other words, don't consume the \n of the previous line)
-                    for (i in 0 until renderer.textArea.numLines) {
+                    for (i in 0 until totalNumLines) {
                         append('\r')
                         append(Ansi.Csi.Codes.Erase.CURSOR_TO_LINE_END.toFullEscapeCode())
-                        if (i < renderer.textArea.numLines - 1) {
+                        if (i < totalNumLines - 1) {
                             append(Ansi.Csi.Codes.Cursor.MOVE_TO_PREV_LINE.toFullEscapeCode())
                         }
                     }

diff --git a/konsole/src/main/kotlin/com/varabyte/konsole/runtime/terminal/Terminal.kt b/konsole/src/main/kotlin/com/varabyte/konsole/runtime/terminal/Terminal.kt
@@ -6,6 +6,7 @@ import kotlinx.coroutines.flow.Flow
  * An interface for abstracting input and output for various terminal implementations.
  */
 interface Terminal : AutoCloseable {
+    val width: Int get() = Int.MAX_VALUE
     fun write(text: String)
     fun read(): Flow<Int>
 }
diff --git a/konsole/src/main/kotlin/com/varabyte/konsole/terminal/SystemTerminal.kt b/konsole/src/main/kotlin/com/varabyte/konsole/terminal/SystemTerminal.kt
@@ -60,6 +60,9 @@ class SystemTerminal : Terminal {
             puts(InfoCmp.Capability.cursor_invisible)
         }
 
+    override val width: Int
+        get() = terminal.width
+
     override fun write(text: String) {
         terminal.writer().print(text)
         terminal.writer().flush()