java - Canvas.drawBitmap 将源代码切成两半

Question

我一直在尝试在 Android 中制作一些 Sprite 动画(这是一项大学练习)，但我遇到了一个奇怪的问题。它没有绘制我定义为源的矩形，而是恰好绘制了该矩形的一半。

这是我的绘图方法的代码

public class Sprite {
Bitmap image;
Point frameSize;
int[] rows;
public int curFrame;
public int curRow;

public void draw(Canvas c, Paint p, Vector2 pos)
{
    Rect src;
    int left = curFrame * frameSize.x;
    int top = curRow * frameSize.y;
    int right = left + frameSize.x;
    int bottom = top + frameSize.y;

    src = new Rect(left, top, right, bottom);
    Rect dest = new Rect((int)pos.x, 0, (int)pos.x + frameSize.x, frameSize.y);

    c.drawBitmap(image, src, dest, p);
}

这是我正在使用的图像

所有帧的大小相同 (44x40)，图像为 440x80，我在调用该方法时将此值指定为 frameSize。

Point 基本上是一个包含一对 x,y 整数的对象。

Vector2 是一个包含一对 x,y float 的对象。

为了调试目的，我还渲染了一些文本。

以下是一些截图:

对不起，截图太大了。我不知道是否有办法在 StackOverflow 中将它们显示得更小

Answer 1

我看不到你的代码。这有什么重要的:

int left = currIndex * peopleWidth;
int top = 40;
int right = left + peopleWidth;
int bottom = 80;
//clip the bitmap to show
Rect src = new Rect(left, top, right, bottom);
//set the display location in view
Rect display = new Rect(0, 0, mWidth, mHeight);
canvas.drawBitmap(mBitmap, src, display, null);

这是我的代码:

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

import com.rajesh.customcamera.R;

import java.util.concurrent.TimeUnit;

import io.reactivex.Observable;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.annotations.NonNull;
import io.reactivex.functions.Consumer;

/**
 * Created by rajesh.zhu on 2017/9/28.
 */

public class MovingPeopleView extends View {
    private static final String TAG = "MovingPeopleView";
    private int defaultWidth = 44;
    private int defaultHeight = 40;
    private int mWidth = 0;
    private int mHeight = 0;
    private int peopleWidth = 44;
    private int peopleHeight = 40;
    private int currIndex = 0;

    private Bitmap mBitmap = null;
    private boolean isRunning = false;

    public MovingPeopleView(Context context) {
        this(context, null);
    }

    public MovingPeopleView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MovingPeopleView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context);
    }

    @Override
    protected synchronized void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);

        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);

        if (widthMode == MeasureSpec.EXACTLY) {
            //match_parent || absolute_value
            mWidth = widthSize;
        } else if (widthMode == MeasureSpec.AT_MOST) {
            //wrap_content
            mWidth = Math.min(defaultWidth, widthSize);
        } else {
            mWidth = defaultWidth;
        }

        if (heightMode == MeasureSpec.EXACTLY) {
            mHeight = heightSize;
        } else if (heightMode == MeasureSpec.AT_MOST) {
            mHeight = Math.min(defaultHeight, heightSize);
        } else {
            mHeight = defaultHeight;
        }

        setMeasuredDimension(mWidth, mHeight);
    }

    private void init(Context context) {
        mBitmap = BitmapFactory.decodeResource(context.getResources(), R.mipmap.icon_moving_people);
        //Log.i(TAG, "Width:" + mBitmap.getWidth() + ", Height:" + mBitmap.getHeight());
        //you can set the peopleWidth and peopleHeight here
    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        int left = currIndex * peopleWidth;
        int top = 40;
        int right = left + peopleWidth;
        int bottom = 80;
        //clip in bitmap to show
        Rect src = new Rect(left, top, right, bottom);
        //set the show location in view
        Rect display = new Rect(0, 0, mWidth, mHeight);
        canvas.drawBitmap(mBitmap, src, display, null);
    }

    public void start() {
        isRunning = true;
        run();
    }

    public void stop() {
        isRunning = false;
    }

    private void run() {
        if (isRunning) {
            Observable
                    .timer(100, TimeUnit.MILLISECONDS)
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribe(new Consumer<Long>() {
                        @Override
                        public void accept(@NonNull Long aLong) throws Exception {
                            currIndex++;
                            if (currIndex == 10) {
                                currIndex = 0;
                            }
                            Log.i(TAG, "run");
                            invalidate();
                            run();
                        }
                    });
        }
    }

    public void recycler() {
        if (mBitmap != null) {
            mBitmap.recycle();
            mBitmap = null;
        }
    }
}

您可以在 XML 中使用它:

<com.rajesh.customcamera.view.MovingPeopleView
    android:id="@+id/moving_people"
    android:layout_width="50dp"
    android:layout_height="50dp" />