我正在尝试在视图中绘制图像,但在尝试维护原始图像的比例时遇到问题。基本上,我有一个小视图,我想在视图中显示部分图像。然后,目的是对图像执行翻译,以便在视图中显示不同的部分。
无论我尝试什么,图像都会自动缩小以适应视图,或者整个图像都可以查看。我尝试使用BitmapDrawable,ImageView和Layout上的设置无济于事。
任何人都知道实现这个目标的好方法吗?
答案 0 :(得分:2)
希望这段代码有帮助。我一个月前用谷歌搜索过它。它为较大图像滚动性能。这整个显示尺寸设置为视图的高度和宽度。你可以改变你的想法。并且也可以保持缩放控制。
public class LargeImageScroller extends Activity {
// Physical display width and height.
private static int displayWidth = 0;
private static int displayHeight = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// displayWidth and displayHeight will change depending on screen
// orientation. To get these dynamically, we should hook onSizeChanged().
// This simple example uses only landscape mode, so it's ok to get them
// once on startup and use those values throughout.
Display display = ((WindowManager)
getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
displayWidth = display.getWidth();
displayHeight = display.getHeight();
// SampleView constructor must be constructed last as it needs the
// displayWidth and displayHeight we just got.
setContentView(new SampleView(this));
}
private static class SampleView extends View {
private static Bitmap bmLargeImage; //bitmap large enough to be scrolled
private static Rect displayRect = null; //rect we display to
private Rect scrollRect = null; //rect we scroll over our bitmap with
private int scrollRectX = 0; //current left location of scroll rect
private int scrollRectY = 0; //current top location of scroll rect
private float scrollByX = 0; //x amount to scroll by
private float scrollByY = 0; //y amount to scroll by
private float startX = 0; //track x from one ACTION_MOVE to the next
private float startY = 0; //track y from one ACTION_MOVE to the next
public SampleView(Context context) {
super(context);
// Destination rect for our main canvas draw. It never changes.
displayRect = new Rect(0, 0, displayWidth, displayHeight);
// Scroll rect: this will be used to 'scroll around' over the
// bitmap in memory. Initialize as above.
scrollRect = new Rect(0, 0, displayWidth, displayHeight);
// Load a large bitmap into an offscreen area of memory.
bmLargeImage = BitmapFactory.decodeResource(getResources(),
R.drawable.testlargeimage);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// Remember our initial down event location.
startX = event.getRawX();
startY = event.getRawY();
break;
case MotionEvent.ACTION_MOVE:
float x = event.getRawX();
float y = event.getRawY();
// Calculate move update. This will happen many times
// during the course of a single movement gesture.
scrollByX = x - startX; //move update x increment
scrollByY = y - startY; //move update y increment
startX = x; //reset initial values to latest
startY = y;
invalidate(); //force a redraw
break;
}
return true; //done with this event so consume it
}
@Override
protected void onDraw(Canvas canvas) {
// Our move updates are calculated in ACTION_MOVE in the opposite direction
// from how we want to move the scroll rect. Think of this as dragging to
// the left being the same as sliding the scroll rect to the right.
int newScrollRectX = scrollRectX - (int)scrollByX;
int newScrollRectY = scrollRectY - (int)scrollByY;
// Don't scroll off the left or right edges of the bitmap.
if (newScrollRectX < 0)
newScrollRectX = 0;
else if (newScrollRectX > (bmLargeImage.getWidth() - displayWidth))
newScrollRectX = (bmLargeImage.getWidth() - displayWidth);
// Don't scroll off the top or bottom edges of the bitmap.
if (newScrollRectY < 0)
newScrollRectY = 0;
else if (newScrollRectY > (bmLargeImage.getHeight() - displayHeight))
newScrollRectY = (bmLargeImage.getHeight() - displayHeight);
// We have our updated scroll rect coordinates, set them and draw.
scrollRect.set(newScrollRectX, newScrollRectY,
newScrollRectX + displayWidth, newScrollRectY + displayHeight);
Paint paint = new Paint();
canvas.drawBitmap(bmLargeImage, scrollRect, displayRect, paint);
// Reset current scroll coordinates to reflect the latest updates,
// so we can repeat this update process.
scrollRectX = newScrollRectX;
scrollRectY = newScrollRectY;
}
}
}
答案 1 :(得分:0)
这可能不是最有效的方法,但是如果你不打算过多地移动它,它就会这样做。 像spritesheet一样对待它,使用Bitmap.createBitmap(位图源,int x,int y,int width,int height)从原始位图获取所需的部分作为自己的位图,然后传入。然后传递它而不是整个位图,它只会与您想要显示的部分一起使用。
答案 2 :(得分:0)
听起来你想在一个较小的View(就像一个窗口)里面有一个很大的ImageView控件,然后将ImageView控件移到其中,所以一次只能看到它的一部分。
虽然不完全确定你是怎么做到的,但是很确定它可以用AbsoluteLayout和一些修补。