我正在尝试使用以下代码在图像上绘制文字：
procedure TfMain.TextToImage(const AText: string; const AImage: TImage);
begin
if NOT Assigned(AImage) then Exit;
AImage.Canvas.BeginScene;
AImage.Canvas.Font.Size := 18;
AImage.Canvas.Font.Family := 'Arial';
AImage.Canvas.Fill.Color := TAlphaColorRec.Dodgerblue;
AImage.Canvas.Font.Style := [TFontStyle.fsbold];
AImage.Canvas.FillText( AImage.AbsoluteRect,
AText,
False,
1,
[TFillTextFlag.RightToLeft],
TTextAlign.taCenter,
TTextAlign.taCenter);
AImage.Canvas.EndScene;
end;
问：为什么上述程序适用于Windows而不适用于android？
答案 0 :(得分：4)
尝试直接在timage的Sub Button1()
Dim myRange, cell As Range
Set myRange = Range("C16:G16")
For Each cell In myRange
If cell.Value > 44.4 Then
cell.Interior.Color = vbRed
ElseIf cell.Value < 38 Then
cell.Interior.Color = vbRed
ElseIf cell.Value >= 38 And cell.Value <= 44.4 Then
cell.Interior.Color = vbGreen
End If
Next
End Sub
上绘制，而不是在TImage的Canvas上绘制。
在尝试访问图像之前，您还需要创建图像的位图：
TBitmap所以正确的代码将是这样的：
AImage.Bitmap := TBitmap.Create(Round(AImage.Width), Round(AImage.Height));
从procedure TfMain.TextToImage(const AText: string; const AImage: TImage);
begin
if NOT Assigned(AImage) then Exit;
AImage.Bitmap := TBitmap.Create(Round(AImage.Width), Round(AImage.Height));
AImage.Bitmap.Canvas.BeginScene;
try
//....
// Use AImage.Bitmap.Canvas as needed
AImage.Bitmap.Canvas.FillText( AImage.AbsoluteRect,
AText,
False,
1,
[],
TTextAlign.Center,
TTextAlign.Center);
finally
AImage.Bitmap.Canvas.EndScene;
end;
end;
事件代码中您会看到：
TImage.Paint所以无论你将在画布上绘制什么，在下一次重新绘制时，它将再次绘制完整的位图，删除你已经完成的工作。
如果您不想触摸位图，则需要覆盖procedure TImage.Paint;
var
R: TRectF;
begin
if (csDesigning in ComponentState) and not Locked and not FInPaintTo then
begin
R := LocalRect;
InflateRect(R, -0.5, -0.5);
Canvas.DrawDashRect(R, 0, 0, AllCorners, AbsoluteOpacity, $A0909090);
end;
UpdateCurrentBitmap;
if FCurrentBitmap <> nil then
DrawBitmap(Canvas, LocalRect, FCurrentBitmap, AbsoluteOpacity);
end;
的{{1}}事件并致电OnPaint
答案 1 :(得分：0)
请参阅以下自定义类ImageView，其中包含Android中的文字。但是需要使用TTF或OTF文件来获取更多字体。
package com.fuzzydev;
import com.fuzzydev.labeledimageview.R;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;
/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return Dejan Ristic
* ----------------------------------------------------------------------------
*/
public class LabeledImageView extends ImageView {
private static final String TAG = "LabeledImageView";
private static final int DEFAULT_TEXT_STYLE = Typeface.NORMAL;
private static final int DEFAULT_TEXT_COLOR = Color.WHITE;
private static final int DEFAULT_SCREEN_LOCATION = 0;
private static final int DEFAULT_X_OFFSET = 30;
private static final int DEFAULT_Y_OFFSET = 30;
private static final float DEFAULT_TEXT_SIZE = 40f;
private float textSize;
private float xPos, yPos;
private float xOffset, yOffset;
private int labelLocation;
private int textStyle;
private int textColor;
private String text;
private String customFont;
private Paint mTextPaint;
public LabeledImageView(Context context) {
super(context);
initWithDefautls();
}
public LabeledImageView(Context context, AttributeSet attrs) {
super(context, attrs);
initWithAttrs(attrs, context);
}
private void initWithDefautls() {
textSize = DEFAULT_TEXT_SIZE;
textStyle = DEFAULT_TEXT_STYLE;
textColor = DEFAULT_TEXT_COLOR;
labelLocation = DEFAULT_SCREEN_LOCATION;
xOffset = DEFAULT_X_OFFSET;
yOffset = DEFAULT_Y_OFFSET;
setTextPaint();
}
private void initWithAttrs(AttributeSet attrs, Context context) {
initAttrs(context, attrs);
setTextPaint();
if (customFont != null) {
setCustomFont(context);
}
}
private void initAttrs(Context context, AttributeSet attrs) {
TypedArray a = context.getTheme().obtainStyledAttributes(attrs,
R.styleable.LabeledImageView, 0, 0);
try {
text = a.getString(R.styleable.LabeledImageView_text);
textSize = a.getFloat(R.styleable.LabeledImageView_textSizePx,
DEFAULT_TEXT_SIZE);
textStyle = a.getInt(R.styleable.LabeledImageView_textStyle,
DEFAULT_TEXT_STYLE);
textColor = a.getInt(R.styleable.LabeledImageView_textColor,
DEFAULT_TEXT_COLOR);
labelLocation = a.getInt(
R.styleable.LabeledImageView_labelPosition,
DEFAULT_SCREEN_LOCATION);
customFont = a.getString(R.styleable.LabeledImageView_customFont);
xOffset = a.getFloat(R.styleable.LabeledImageView_xOffset,
DEFAULT_X_OFFSET);
yOffset = a.getFloat(R.styleable.LabeledImageView_yOffset,
DEFAULT_Y_OFFSET);
;
} finally {
a.recycle();
}
}
private void setCustomFont(Context ctx) {
Typeface tf = null;
try {
tf = Typeface.createFromAsset(ctx.getAssets(), customFont);
} catch (Exception e) {
Log.e(TAG, "Could not get typeface: " + e.getMessage());
}
mTextPaint.setTypeface(tf);
}
private void setLabelLocation() {
switch (labelLocation) {
case 0: // Top Left
xPos = xOffset;
yPos = yOffset;
break;
case 1: // Top Right
xPos = getWidth() - mTextPaint.measureText(text) - xOffset;
yPos = yOffset;
break;
case 2: // Bottom Left
xPos = xOffset;
yPos = getHeight() - yOffset;
break;
case 3: // Bottom Right
xPos = getWidth() - mTextPaint.measureText(text) - xOffset;
yPos = getHeight() - yOffset;
break;
case 4: // Top Center
xPos = (getWidth() / 2) - (mTextPaint.measureText(text) / 2);
yPos = yOffset;
break;
case 5: // Bottom Center
xPos = (getWidth() / 2) - (mTextPaint.measureText(text) / 2);
yPos = getHeight() - yOffset;
break;
case 6: // Center
xPos = (getWidth() / 2) - (mTextPaint.measureText(text) / 2);
yPos = (getHeight() / 2);
default:
break;
}
}
@Override
public void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
setLabelLocation();
}
private void setTextPaint() {
mTextPaint = new Paint();
mTextPaint.setTextSize(textSize);
mTextPaint.setColor(textColor);
mTextPaint.setTypeface(Typeface.defaultFromStyle(textStyle));
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (text != null) {
canvas.drawText(text, xPos, yPos, mTextPaint);
}
}
public void setTextSize(float textSize) {
this.textSize = textSize;
}
public void setCustomFont(String customFont) {
this.customFont = customFont;
}
public void setLabelLocation(int labelLocation) {
this.labelLocation = labelLocation;
}
public void setyOffset(float yOffset) {
this.yOffset = yOffset;
}
public void setxOffset(float xOffset) {
this.xOffset = xOffset;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public void setTextStyle(int textStyle) {
this.textStyle = textStyle;
}
public void setTextColor(int textColor) {
this.textColor = textColor;
}
}
请参阅本
中上述类的实现https://github.com/DejanRistic/LabeledImageView/tree/master/src/com/fuzzydev
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