React Suspense 事件可视化 - 绘制单个悬挂事件

"_drawSingleSuspenseEvent(\n context: CanvasRenderingContext2D,\n rect: Rect,\n event: SuspenseEvent,\n baseY: number,\n scaleFactor: number,\n showHoverHighlight: boolean,\n ) {\n const {frame} = this;\n const {\n componentName,\n depth,\n duration,\n phase,\n promiseName,\n resolution,\n timestamp,\n warning,\n } = event;\n\n baseY += depth * ROW_WITH_BORDER_HEIGHT;\n\n let fillStyle = ((null: any): string);\n if (warning !== null) {\n fillStyle = showHoverHighlight\n ? COLORS.WARNING_BACKGROUND_HOVER\n : COLORS.WARNING_BACKGROUND;\n } else {\n switch (resolution) {\n case 'rejected':\n fillStyle = showHoverHighlight\n ? COLORS.REACT_SUSPENSE_REJECTED_EVENT_HOVER\n : COLORS.REACT_SUSPENSE_REJECTED_EVENT;\n break;\n case 'resolved':\n fillStyle = showHoverHighlight\n ? COLORS.REACT_SUSPENSE_RESOLVED_EVENT_HOVER\n : COLORS.REACT_SUSPENSE_RESOLVED_EVENT;\n break;\n case 'unresolved':\n fillStyle = showHoverHighlight\n ? COLORS.REACT_SUSPENSE_UNRESOLVED_EVENT_HOVER\n : COLORS.REACT_SUSPENSE_UNRESOLVED_EVENT;\n break;\n }\n }\n\n const xStart = timestampToPosition(timestamp, scaleFactor, frame);\n\n // Pending suspense events (ones that never resolved) won't have durations.\n // So instead we draw them as diamonds.\n if (duration === null) {\n const size = PENDING_SUSPENSE_EVENT_SIZE;\n const halfSize = size / 2;\n\n baseY += (SUSPENSE_EVENT_HEIGHT - PENDING_SUSPENSE_EVENT_SIZE) / 2;\n\n const y = baseY + halfSize;\n\n const suspenseRect: Rect = {\n origin: {\n x: xStart - halfSize,\n y: baseY,\n },\n size: {width: size, height: size},\n };\n if (!rectIntersectsRect(suspenseRect, rect)) {\n return; // Not in view\n }\n\n context.beginPath();\n context.fillStyle = fillStyle;\n context.moveTo(xStart, y - halfSize);\n context.lineTo(xStart + halfSize, y);\n context.lineTo(xStart, y + halfSize);\n context.lineTo(xStart - halfSize, y);\n context.fill();\n } else {\n const xStop = timestampToPosition(\n timestamp + duration,\n scaleFactor,\n frame,\n );\n const eventRect: Rect = {\n origin: {\n x: xStart,\n y: baseY,\n },\n size: {width: xStop - xStart, height: SUSPENSE_EVENT_HEIGHT},\n };\n if (!rectIntersectsRect(eventRect, rect)) {\n return; // Not in view\n }\n\n const width = durationToWidth(duration, scaleFactor);\n if (width < 1) {\n return; // Too small to render at this zoom level\n }\n\n const drawableRect = intersectionOfRects(eventRect, rect);\n context.beginPath();\n context.fillStyle = fillStyle;\n context.fillRect(\n drawableRect.origin.x,\n drawableRect.origin.y,\n drawableRect.size.width,\n drawableRect.size.height,\n );\n\n let label = 'suspended';\n if (promiseName != null) {\n label = promiseName;\n } else if (componentName != null) {\n label = ${componentName} ${label};\n }\n if (phase !== null) {\n label += during ${phase};\n }\n if (resolution !== 'unresolved') {\n label += - ${formatDuration(duration)};\n }\n\n drawText(label, context, eventRect, drawableRect);\n }\n }\n中文回答函数功能以及函数执行过程\n\n内容：这段代码是一个绘制单个悬挂事件的函数。它接收一个CanvasRenderingContext2D对象用于绘制，一个Rect对象表示绘制区域，一个SuspenseEvent对象表示悬挂事件的属性，一个基准Y坐标用于确定事件的垂直位置，一个缩放因子用于确定事件的水平位置，一个布尔值表示是否显示悬停高亮。\n\n函数首先根据事件的深度确定事件的垂直位置。然后根据事件的属性确定填充颜色。如果事件有警告属性，则使用警告的颜色；否则根据事件的解决状态确定颜色。\n\n接下来，函数根据事件的时间戳和缩放因子确定事件的水平位置。如果事件没有持续时间，则绘制一个菱形表示事件未解决。否则，绘制一个矩形表示事件的持续时间。\n\n最后，函数绘制事件的标签，并根据绘制区域和事件区域的交集来确定绘制的位置。\n\n函数的执行过程如下：\n1. 根据事件的深度计算事件的垂直位置。\n2. 根据事件的属性确定填充颜色。\n3. 根据事件的时间戳和缩放因子计算事件的水平位置。\n4. 如果事件没有持续时间，则绘制一个菱形表示事件未解决。\n5. 如果事件有持续时间，则绘制一个矩形表示事件的持续时间。\n6. 绘制事件的标签。\n7. 根据绘制区域和事件区域的交集确定绘制的位置。