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优化文本绘制计算逻辑 #585

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优化文本绘制计算逻辑 #585

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66 changes: 28 additions & 38 deletions wheelview/src/main/java/com/contrarywind/view/WheelView.java
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Original file line number Diff line number Diff line change
Expand Up @@ -429,12 +429,6 @@ protected void onDraw(Canvas canvas) {
canvas.drawLine(0.0F, secondLineY, measuredWidth, secondLineY, paintIndicator);
}

//只显示选中项Label文字的模式，并且Label文字不为空，则进行绘制
if (!TextUtils.isEmpty(label) && isCenterLabel) {
//绘制文字，靠右并留出空隙
int drawRightContentStart = measuredWidth - getTextWidth(paintCenterText, label);
canvas.drawText(label, drawRightContentStart - CENTER_CONTENT_OFFSET, centerY, paintCenterText);
}

counter = 0;
while (counter < itemsVisible) {
Expand All @@ -453,19 +447,22 @@ protected void onDraw(Canvas canvas) {
// 根据当前角度计算出偏差系数，用以在绘制时控制文字的 水平移动 透明度 倾斜程度
float offsetCoefficient = (float) Math.pow(Math.abs(angle) / 90f, 2.2);
//获取内容文字
String contentText;
String outerText;

//如果是label每项都显示的模式，并且item内容不为空、label 也不为空
if (!isCenterLabel && !TextUtils.isEmpty(label) && !TextUtils.isEmpty(getContentText(visibles[counter]))) {
contentText = getContentText(visibles[counter]) + label;
outerText = getContentText(visibles[counter]) + label;
} else {
contentText = getContentText(visibles[counter]);
outerText = getContentText(visibles[counter]);
}

reMeasureTextSize(contentText);
//中间项文本内容
String centerText = getContentText(visibles[counter]) + label;

reMeasureTextSize(centerText);
//计算开始绘制的位置
measuredCenterContentStart(contentText);
measuredOutContentStart(contentText);
measuredCenterContentStart();
measuredOutContentStart();
float translateY = (float) (radius - Math.cos(radian) * radius - (Math.sin(radian) * maxTextHeight) / 2D);
//根据Math.sin(radian)来更改canvas坐标系原点，然后缩放画布，使得文字高度进行缩放，形成弧形3d视觉差
canvas.translate(0.0F, translateY);
Expand All @@ -475,31 +472,31 @@ protected void onDraw(Canvas canvas) {
canvas.save();
canvas.clipRect(0, 0, measuredWidth, firstLineY - translateY);
canvas.scale(1.0F, (float) Math.sin(radian) * SCALE_CONTENT);
canvas.drawText(contentText, drawOutContentStart, maxTextHeight, paintOuterText);
canvas.drawText(outerText, drawOutContentStart, maxTextHeight, paintOuterText);
canvas.restore();
canvas.save();
canvas.clipRect(0, firstLineY - translateY, measuredWidth, (int) (itemHeight));
canvas.scale(1.0F, (float) Math.sin(radian) * 1.0F);
canvas.drawText(contentText, drawCenterContentStart, maxTextHeight - CENTER_CONTENT_OFFSET, paintCenterText);
canvas.drawText(centerText, drawCenterContentStart, maxTextHeight - CENTER_CONTENT_OFFSET, paintCenterText);
canvas.restore();
} else if (translateY <= secondLineY && maxTextHeight + translateY >= secondLineY) {
// 条目经过第二条线
canvas.save();
canvas.clipRect(0, 0, measuredWidth, secondLineY - translateY);
canvas.scale(1.0F, (float) Math.sin(radian) * 1.0F);
canvas.drawText(contentText, drawCenterContentStart, maxTextHeight - CENTER_CONTENT_OFFSET, paintCenterText);
canvas.drawText(centerText, drawCenterContentStart, maxTextHeight - CENTER_CONTENT_OFFSET, paintCenterText);
canvas.restore();
canvas.save();
canvas.clipRect(0, secondLineY - translateY, measuredWidth, (int) (itemHeight));
canvas.scale(1.0F, (float) Math.sin(radian) * SCALE_CONTENT);
canvas.drawText(contentText, drawOutContentStart, maxTextHeight, paintOuterText);
canvas.drawText(outerText, drawOutContentStart, maxTextHeight, paintOuterText);
canvas.restore();
} else if (translateY >= firstLineY && maxTextHeight + translateY <= secondLineY) {
// 中间条目
canvas.clipRect(0, 0, measuredWidth, maxTextHeight);
//让文字居中
float Y = maxTextHeight - CENTER_CONTENT_OFFSET;//因为圆弧角换算的向下取值，导致角度稍微有点偏差，加上画笔的基线会偏上，因此需要偏移量修正一下
canvas.drawText(contentText, drawCenterContentStart, Y, paintCenterText);
canvas.drawText(centerText, drawCenterContentStart, Y, paintCenterText);

//设置选中项
selectedItem = preCurrentIndex - (itemsVisible / 2 - counter);
Expand All @@ -514,7 +511,7 @@ protected void onDraw(Canvas canvas) {
// 控制透明度
paintOuterText.setAlpha((int) ((1 - offsetCoefficient) * 255));
// 控制文字水平偏移距离
canvas.drawText(contentText, drawOutContentStart + textXOffset * offsetCoefficient, maxTextHeight, paintOuterText);
canvas.drawText(outerText, drawOutContentStart + textXOffset * offsetCoefficient, maxTextHeight, paintOuterText);
canvas.restore();
}
canvas.restore();
Expand Down Expand Up @@ -576,42 +573,36 @@ private String getContentText(Object item) {
return item.toString();
}

private void measuredCenterContentStart(String content) {
Rect rect = new Rect();
paintCenterText.getTextBounds(content, 0, content.length(), rect);
private void measuredCenterContentStart() {
switch (mGravity) {
case Gravity.CENTER://显示内容居中
if (isOptions || label == null || label.equals("") || !isCenterLabel) {
drawCenterContentStart = (int) ((measuredWidth - rect.width()) * 0.5);
} else {//只显示中间label时，时间选择器内容偏左一点，留出空间绘制单位标签
drawCenterContentStart = (int) ((measuredWidth - rect.width()) * 0.25);
}
drawCenterContentStart = (int) (measuredWidth * 0.5);
paintCenterText.setTextAlign(Paint.Align.CENTER);
break;
case Gravity.LEFT:
drawCenterContentStart = 0;
paintCenterText.setTextAlign(Paint.Align.LEFT);
break;
case Gravity.RIGHT://添加偏移量
drawCenterContentStart = measuredWidth - rect.width() - (int) CENTER_CONTENT_OFFSET;
case Gravity.RIGHT:
drawCenterContentStart = measuredWidth;
paintCenterText.setTextAlign(Paint.Align.RIGHT);
break;
}
}

private void measuredOutContentStart(String content) {
Rect rect = new Rect();
paintOuterText.getTextBounds(content, 0, content.length(), rect);
private void measuredOutContentStart() {
switch (mGravity) {
case Gravity.CENTER:
if (isOptions || label == null || label.equals("") || !isCenterLabel) {
drawOutContentStart = (int) ((measuredWidth - rect.width()) * 0.5);
} else {//只显示中间label时，时间选择器内容偏左一点，留出空间绘制单位标签
drawOutContentStart = (int) ((measuredWidth - rect.width()) * 0.25);
}
drawOutContentStart = (int) (measuredWidth * 0.5);
paintOuterText.setTextAlign(Paint.Align.CENTER);
break;
case Gravity.LEFT:
drawOutContentStart = 0;
paintOuterText.setTextAlign(Paint.Align.LEFT);
break;
case Gravity.RIGHT:
drawOutContentStart = measuredWidth - rect.width() - (int) CENTER_CONTENT_OFFSET;
drawOutContentStart = measuredWidth;
paintOuterText.setTextAlign(Paint.Align.RIGHT);
break;
}
}
Expand Down Expand Up @@ -756,7 +747,6 @@ public void setTextColorOut(int textColorOut) {

public void setTextColorCenter(int textColorCenter) {
if (textColorCenter != 0) {

this.textColorCenter = textColorCenter;
paintCenterText.setColor(this.textColorCenter);
}
Expand Down