我正在设计一个绘图应用程序,用户可以在其中从图库中导入图像,然后按比例放大或缩小以适应屏幕宽度或高度。以便用户可以使用以下代码在导入的图片上绘图。
我在扩展View
,命名DrawView
。与DrawView
screenwidth相同,但它的高度小于screenheight,因为它上面有一些按钮,将DrawView放在功能按钮下方的Screen底部,所以我声明DrawViewHeight
.
有关变量的维度和结果的示例,请参见下文。
问题:
位图可以正确加载和缩放以适应DrawView
.
但是,它位于DrawView
. 我想把它放在屏幕中间,所以我添加了以下代码,但仍然失败。
bitmapCanvas.drawBitmap(bitmap, x_adjustment, y_adjustment, null);
如何进一步修改导入的图像(在导入时解码并复制为位图)放置在 的中心DrawView
,在加载的缩放位图图像的上方和下方以及左侧和右侧有空白区域(例如白色)?
注意:图像周围的空间不得由用户绘制。
代码:
声明:
private Bitmap bitmap; // drawing area for display or saving
private Canvas bitmapCanvas; // used to draw on bitmap
OnSizeChanged:
public void onSizeChanged(int w, int h, int oldW, int oldH)
{
super.onSizeChanged(w, h, oldW, oldH);
DrawViewWidth = w;
DrawViewHeight = h;
bitmap = Bitmap.createBitmap(getWidth(), DrawViewHeight, Bitmap.Config.ARGB_8888);
bitmapCanvas = new Canvas(bitmap);
bitmap.eraseColor(Color.WHITE); // erase the BitMap with white
}
绘制:
@Override
protected void onDraw(Canvas canvas) // called each time this View is drawn
{
canvas.drawBitmap(bitmap, 0, 0, paintScreen);
}
加载图片:
public void load_pic(final String picturePath)
{
// get screen dimension first
WindowManager wm = (WindowManager) context_new.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
final int screenWidth = display.getWidth();
final int screenHeight = display.getHeight();
//get importing bitmap dimension
Options op = new Options();
op.inJustDecodeBounds = true;
Bitmap pic_to_be_imported = BitmapFactory.decodeFile(picturePath, op);
final int x_pic = op.outWidth;
final int y_pic = op.outHeight;
// scaling
final int IMAGE_MAX_SIZE= (int) Math.max(DrawViewWidth, DrawViewHeight);
int scale = 1;
if (op.outHeight > IMAGE_MAX_SIZE || op.outWidth > IMAGE_MAX_SIZE) {
scale = (int)Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE / (double) Math.max(op.outHeight, op.outWidth)) / Math.log(0.5))); }
final BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
// Start loading image to the DrawView
if ((x_pic > DrawViewWidth) || (y_pic > DrawViewHeight))
{
AlertDialog.Builder onBackBuilder = new AlertDialog.Builder(context_new);
onBackBuilder.setPositiveButton(R.string.buttontext_create_load_pic_stretch, new DialogInterface.OnClickListener()
{
//skipped
}
onBackBuilder.setNegativeButton(R.string.buttontext_create_load_pic_keep_scale, new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int id)
{
float xratio = (float) x_pic / (float) screenWidth;
float yratio = (float) y_pic / (float) DrawViewHeight;
int adjusted_x = 0;
int adjusted_y = 0;
if (xratio >= yratio) {adjusted_x = screenWidth; adjusted_y = (int) (y_pic / xratio);}
if (xratio < yratio) {adjusted_y = DrawViewHeight; adjusted_x = (int) (x_pic / yratio);}
bitmap = (BitmapFactory.decodeFile(picturePath, o2));
bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);
bitmap = Bitmap.createScaledBitmap(bitmap, adjusted_x, adjusted_y, true);
int x_adjustment = (screenWidth - adjusted_x) /2;
int y_adjustment = (DrawViewHeight -adjusted_y) /2;
bitmapCanvas.drawBitmap(bitmap, x_adjustment, y_adjustment, null);
// How to modify to put to center of DrawView????
invalidate();
}
});
AlertDialog alert = onBackBuilder.create();
alert.show();
}
变量的维度和结果示例:
Screen : 480W * 800H
DrawView : 480W * 590H
Original image : 3264W * 2448H
Scaled image : adjusted_x=480 (meet screenwidth), adjusted_y=360
x_adjustment : 0
y-adjustment : 115
布局.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<com.pearmak.drawing.DrawView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:layout_gravity="center_vertical|center_horizontal|center"
android:background="@drawable/drawview_border" />
</RelativeLayout>