以下为自定义View,继承自ImageView,可实现对图片进行编辑,包括普通涂鸦、画圆、画矩形、画箭头以及写字。
并且,可以对线条大小、线条颜色、字体大小、字体颜色进行设置。另外,实现了文字自动换行、移动文字位置、撤销等功能。
主要用到了Canvas、Paint、TextPaint、StaticLayout等Android中的图形图像方面和自定义View的技术。
下面直接上代码:
package au.com.joincc.secusoft.view;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.text.DynamicLayout;
import android.text.Layout;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.ImageView;
import java.io.FileOutputStream;
import java.io.IOException;
import au.com.joincc.secusoft.R;
/**
* Created by Administrator on 2017/9/4.
* 自定义View.使用Canvas、Paint等来实现图片编辑功能(包括普通涂鸦、画圆、画矩形、画箭头、写字)
*/
public class GraffitiView extends ImageView {
private Paint paint; //画笔
private Bitmap originalBitmap; //源图
private Bitmap newBitmap;
private Bitmap finalBitmap; //最终保存时的图片
private Bitmap finalOvalBitmap;
private Bitmap finalRectBitmap;
private Bitmap finalArrowBitmap;
private Bitmap finalTextBitmap;
private float clickX = 0; //触摸时的x坐标
private float clickY = 0; //触摸时的y坐标
private float startX = 0; //每次绘制起点的x坐标
private float startY = 0; //每次绘制起点的y坐标
private boolean isEdit = false; //是否允许对图片进行编辑
private boolean isMove = true; //是否进行绘制
private boolean isClear = false; //是否进行清空
private int drawType = 0; //绘制类型:0---线条;1---圆;2---矩形;3---箭头;4---文字
private String text;
private int color = Color.RED; //画笔颜色
private float strokeWidth = 4.0f; //涂鸦线条的宽度
private int textSize = 18; //字体大小
private int textColor = getResources().getColor(R.color.red); //文字颜色
private int mScreenWidth;
private int mScreenHeight;
private String filePath;
public GraffitiView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void setFilePath(String filePath) {
this.filePath = filePath;
//根据原位图的大小创建一个新位图,得到的位图是可变的
DisplayMetrics dm = getResources().getDisplayMetrics();
mScreenWidth = dm.widthPixels;
mScreenHeight = dm.heightPixels;
originalBitmap = BitmapFactory.decodeFile(filePath).copy(Bitmap.Config.ARGB_8888, true);
// new1Bitmap = Bitmap.createBitmap(originalBitmap); //得到一个不可变位图
finalBitmap = Bitmap.createScaledBitmap(originalBitmap, mScreenWidth, mScreenHeight, true);
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
switch (drawType) {
case 0:
canvas.drawBitmap(handWriting(), 0, 0, null);
break;
case 1:
canvas.drawBitmap(drawOval(), 0, 0, null);
break;
case 2:
canvas.drawBitmap(drawRect(), 0, 0, null);
break;
case 3:
canvas.drawBitmap(drawArrow(), 0, 0, null);
break;
case 4:
canvas.drawBitmap(writeText(), 0, 0, null);
break;
}
}
/**
* 画线条
* @return
*/
public Bitmap handWriting() {
if (isClear) {
isClear = false;
finalBitmap = newBitmap;
return finalBitmap;
} else {
Bitmap bitmap = Bitmap.createScaledBitmap(finalBitmap, mScreenWidth, mScreenHeight, true);
Canvas canvas = new Canvas(bitmap);
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setAntiAlias(true);
paint.setColor(color);
paint.setStrokeWidth(strokeWidth);
if (isMove) { //当移动时绘制
canvas.drawLine(startX, startY, clickX, clickY, paint); //在画布上画线(通过起点、终点和画笔)
}
//起点需要不断变化,否则画出来的不是线而是面,因为起点一直不变
startX = clickX;
startY = clickY;
finalBitmap = bitmap;
return finalBitmap;
}
}
/**
* 画椭圆(包括圆,圆是一种特殊的椭圆)
* @return
*/
public Bitmap drawOval() {
if (isClear) {
isClear = false;
finalBitmap = newBitmap;
return finalBitmap;
} else {
Bitmap bitmap = Bitmap.createScaledBitmap(finalBitmap, mScreenWidth, mScreenHeight, true);
Canvas canvas = new Canvas(bitmap);
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setAntiAlias(true);
paint.setColor(color);
paint.setStrokeWidth(strokeWidth);
if (isMove) {
canvas.drawOval(new RectF(startX, startY, clickX, clickY), paint);
}
finalOvalBitmap = bitmap;
return finalOvalBitmap;
}
}
/**
* 画矩形
* @return
*/
public Bitmap drawRect() {
if (isClear) {
isClear = false;
finalBitmap = newBitmap;
return finalBitmap;
} else {
Bitmap bitmap = Bitmap.createScaledBitmap(finalBitmap, mScreenWidth, mScreenHeight, true);
Canvas canvas = new Canvas(bitmap);
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setAntiAlias(true);
paint.setColor(color);
paint.setStrokeWidth(strokeWidth);
if (isMove) {
canvas.drawRect(startX, startY, clickX, clickY, paint);
}
finalRectBitmap = bitmap;
return finalRectBitmap;
}
}
/**
* 画箭头
*/
public Bitmap drawArrow() {
if (isClear) {
isClear = false;
finalBitmap = newBitmap;
return finalBitmap;
} else {
Bitmap bitmap = Bitmap.createScaledBitmap(finalBitmap, mScreenWidth, mScreenHeight, true);
Canvas canvas = new Canvas(bitmap);
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setAntiAlias(true);
paint.setColor(color);
paint.setStrokeWidth(strokeWidth);
if (isMove) {
drawArrow(startX, startY, clickX, clickY, canvas, paint);
}
finalArrowBitmap = bitmap;
return finalArrowBitmap;
}
}
public void drawArrow(float startX, float startY, float endX, float endY, Canvas canvas, Paint paint) {
double H = 10; //箭头高度
double L = 6; //底边的一半
int x3 = 0;
int y3 = 0;
int x4 = 0;
int y4 = 0;
double awrad = Math.atan(L / H); //箭头角度
double arraow_len = Math.sqrt(L * L + H * H); //箭头的长度
double[] arrXY_1 = rotateVec(endX - startX, endY - startY, awrad, true, arraow_len);
double[] arrXY_2 = rotateVec(endX - startX, endY - startY, -awrad, true, arraow_len);
double x_3 = endX - arrXY_1[0]; //(x3,y3)是第一端点
double y_3 = endY - arrXY_1[1];
double x_4 = endX - arrXY_2[0]; //(x4,y4)是第二端点
double y_4 = endY - arrXY_2[1];
Double X3 = new Double(x_3);
x3 = X3.intValue();
Double Y3 = new Double(y_3);
y3 = Y3.intValue();
Double X4 = new Double(x_4);
x4 = X4.intValue();
Double Y4 = new Double(y_4);
y4 = Y4.intValue();
//画线
canvas.drawLine(startX, startY, endX, endY, paint);
Path triangle = new Path();
triangle.moveTo(endX, endY);
triangle.lineTo(x3, y3);
triangle.lineTo(x4, y4);
triangle.close();
canvas.drawPath(triangle, paint);
}
public double[] rotateVec(float px, float py, double ang, boolean isChLen, double newLen) {
double mathstr[] = new double[2];
//矢量旋转函数,参数含义分别是x分量、y分量、旋转角、是否改变长度、新长度
double vx = px * Math.cos(ang) - py * Math.sin(ang);
double vy = px * Math.sin(ang) + py * Math.cos(ang);
if (isChLen) {
double d = Math.sqrt(vx * vx + vy * vy);
vx = vx / d * newLen;
vy = vy / d * newLen;
mathstr[0] = vx;
mathstr[1] = vy;
}
return mathstr;
}
/**
* 在图片上写字
* @param text
*/
public void writeTextToBitmap(String text) {
drawType = 4;
this.text = text;
invalidate();
}
public Bitmap writeText() {
if (isClear) {
isClear = false;
finalBitmap = newBitmap;
finalTextBitmap = finalBitmap;
return finalBitmap;
} else {
Bitmap bitmap = Bitmap.createScaledBitmap(finalBitmap, mScreenWidth, mScreenHeight, true);
Canvas canvas = new Canvas(bitmap);
TextPaint textPaint = new TextPaint();
textPaint.setColor(textColor);
textPaint.setTextSize(textSize * getResources().getDisplayMetrics().density);
textPaint.setAntiAlias(true);
StaticLayout staticLayout = new StaticLayout(text, textPaint, mScreenWidth * 3 / 4, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
canvas.translate(clickX, clickY);
staticLayout.draw(canvas);
finalTextBitmap = bitmap;
return finalTextBitmap;
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
clickX = event.getX();
clickY = event.getY();
if (event.getAction() == MotionEvent.ACTION_DOWN) {
//当按下并不移动时,刷新并记下按下时的坐标点但不绘制
startX = clickX;
startY = clickY;
isMove = false;
invalidate();
return true;
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
//当移动时,进行绘制,从按下的坐标点起
if (isEdit) {
isMove = true;
}
invalidate();
return true;
} else if (event.getAction() == MotionEvent.ACTION_UP) {
isMove = false;
switch (drawType) {
case 1:
finalBitmap = finalOvalBitmap;
break;
case 2:
finalBitmap = finalRectBitmap;
break;
case 3:
finalBitmap = finalArrowBitmap;
break;
}
return true;
}
return super.onTouchEvent(event);
}
/**
* 设置画的类型
* @param drawType
*/
public void setDrawType(int drawType) {
if (this.drawType == 4) {
finalBitmap = finalTextBitmap;
}
this.drawType = drawType;
}
/**
* 设置是否允许对图片进行编辑
* @param isEdit
*/
public void setIdEdit(boolean isEdit) {
this.isEdit = isEdit;
}
/**
* 清空
*/
public void clear() {
isClear = true;
newBitmap = Bitmap.createScaledBitmap(originalBitmap, mScreenWidth, mScreenHeight, true);
invalidate();
}
/**
* 设置画笔颜色
* @param color
*/
public void setColor(int color) {
this.color = color;
}
/**
* 设置画笔的宽度
* @param strokeWidth
*/
public void setStyle(float strokeWidth) {
this.strokeWidth = strokeWidth;
}
/**
* 设置字体大小
* @param textSize
*/
public void setTextSize(int textSize) {
this.textSize = textSize;
}
/**
* 设置字体颜色
* @param textColor
*/
public void setTextColor(int textColor) {
this.textColor = textColor;
}
/**
* 保存图片
*/
public void saveBitmap(Handler handler) {
if (drawType == 4) {
finalBitmap = finalTextBitmap;
}
if (!filePath.equals(Environment.getExternalStorageDirectory().getPath() + "/JCamera/image.jpeg")) {
int bitmapWidth = originalBitmap.getWidth();
int bitmapHeight = originalBitmap.getHeight();
finalBitmap = Bitmap.createScaledBitmap(finalBitmap, bitmapWidth, bitmapHeight, true);
}
FileOutputStream fos = null;
try {
fos = new FileOutputStream(filePath);
finalBitmap.compress(Bitmap.CompressFormat.PNG, 90, fos);
fos.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
handler.sendMessage(Message.obtain());
}
}
}
以上代码结构很清晰,注释写的也比较清楚。读者可以直接拿去使用。
关于一些基础知识,如果不明白,可以查看我的另一篇文章Canvas、Paint、TextPaint、StaticLayout,或者通过查看Google文档等方式自行了解。