using viewport relative coordinate

addons/addon-webgl/src/WebglRenderer.ts

@@ -391,6 +391,7 @@ export class WebglRenderer extends Disposable implements IRenderer {
     end = clamp(end, terminal.rows - 1, 0);
 
     const cursorY = this._terminal.buffer.active.baseY + this._terminal.buffer.active.cursorY;
+    const viewportRelativeCursorY = cursorY - terminal.buffer.ydisp;
     // in case cursor.x == cols adjust visual cursor to cols - 1
     const cursorX = Math.min(this._terminal.buffer.active.cursorX, terminal.cols - 1);
     let lastCursorX = -1;
@@ -449,7 +450,7 @@ export class WebglRenderer extends Disposable implements IRenderer {
           if (x === cursorX) {
             this._model.cursor = {
               x: cursorX,
-              y: this._terminal.buffer.active.cursorY,
+              y: viewportRelativeCursorY,
               width: cell.getWidth(),
               style: this._coreBrowserService.isFocused ?
                 (terminal.options.cursorStyle || 'block') : terminal.options.cursorInactiveStyle,

test/playwright/SharedRendererTests.ts

@@ -1171,9 +1171,35 @@ export function injectSharedRendererTests(ctx: ISharedRendererTestContext): void
       await ctx.value.proxy.selectAll();
       await pollFor(ctx.value.page, () => getCellColor(ctx.value, 1, 1), [0, 0, 255, 255]);
     });
+    test('#4799: cursor should be in the correct position', async () => {
+      const theme: ITheme = {
+        cursor: '#0000FF'
+      };
+      await ctx.value.page.evaluate(`window.term.options.theme = ${JSON.stringify(theme)};`);
+      for (let index = 0; index < 160; index++) {
+        await ctx.value.proxy.writeln(``);
+      }
+      await ctx.value.proxy.focus();
+      await ctx.value.proxy.write('\x1b[A');
+      await ctx.value.proxy.write('\x1b[A');
+      await ctx.value.proxy.scrollLines(-2);
+      const rows = await ctx.value.proxy.rows;
+      // block cursor style
+      await pollFor(ctx.value.page, () => getCellColor(ctx.value, 1, rows), [0, 0, 255, 255]);
+      await ctx.value.proxy.blur();
+      frameDetails = undefined;
+      // outlink cursor style
+      await pollFor(ctx.value.page, () => getCellColor(ctx.value, 1, rows), [0, 0, 0, 255]);
+      await pollFor(ctx.value.page, () => getCellColor(ctx.value, 1, rows, CellColorPosition.FIRST), [0, 0, 255, 255]);
+    });
   });
 }
 
+enum CellColorPosition {
+  CENTER = 0,
+  FIRST = 1
+}
+
 /**
  * Injects shared renderer tests where it's required to re-initialize the terminal for each test.
  * This is much slower than just calling `Terminal.reset` but testing some features needs this
@@ -1214,11 +1240,16 @@ export function injectSharedRendererTestsStandalone(ctx: ISharedRendererTestCont
  * @param col The 1-based column index to get the color for.
  * @param row The 1-based row index to get the color for.
  */
-function getCellColor(ctx: ITestContext, col: number, row: number): MaybeAsync<[red: number, green: number, blue: number, alpha: number]> {
+function getCellColor(ctx: ITestContext, col: number, row: number, position: CellColorPosition = CellColorPosition.CENTER): MaybeAsync<[red: number, green: number, blue: number, alpha: number]> {
   if (!frameDetails) {
     return getFrameDetails(ctx).then(frameDetails => getCellColorInner(frameDetails, col, row));
   }
-  return getCellColorInner(frameDetails, col, row);
+  switch (position) {
+    case CellColorPosition.CENTER:
+      return getCellColorInner(frameDetails, col, row);
+    case CellColorPosition.FIRST:
+      return getCellColorFirstPoint(frameDetails, col, row);
+  }
 }
 
 let frameDetails: { cols: number, rows: number, decoded: IImage32 } | undefined = undefined;
@@ -1244,6 +1275,17 @@ function getCellColorInner(frameDetails: { cols: number, rows: number, decoded:
   return Array.from(frameDetails.decoded.data.slice(i, i + 4)) as [number, number, number, number];
 }
 
+function getCellColorFirstPoint(frameDetails: { cols: number, rows: number, decoded: IImage32 }, col: number, row: number): [red: number, green: number, blue: number, alpha: number] {
+  const cellSize = {
+    width: frameDetails.decoded.width / frameDetails.cols,
+    height: frameDetails.decoded.height / frameDetails.rows
+  };
+  const x = Math.floor((col - 1/* 1- to 0-based index */) * cellSize.width);
+  const y = Math.floor((row - 1/* 1- to 0-based index */) * cellSize.height);
+  const i = (y * frameDetails.decoded.width + x) * 4/* 4 channels per pixel */;
+  return Array.from(frameDetails.decoded.data.slice(i, i + 4)) as [number, number, number, number];
+}
+
 const COLORS_16_TO_255 = [
   '#000000', '#00005f', '#000087', '#0000af', '#0000d7', '#0000ff', '#005f00', '#005f5f', '#005f87', '#005faf', '#005fd7', '#005fff', '#008700', '#00875f', '#008787', '#0087af',
   '#0087d7', '#0087ff', '#00af00', '#00af5f', '#00af87', '#00afaf', '#00afd7', '#00afff', '#00d700', '#00d75f', '#00d787', '#00d7af', '#00d7d7', '#00d7ff', '#00ff00', '#00ff5f',