【发布时间】：2016-09-19 21:52:23
【问题描述】：
如何在图像上写文字然后将其保存在 Android 中？
基本上我想让用户在我的相机应用程序将点击的图像上写一些东西。我可以在相机预览中使用 onDraw 方法编写并向他们展示。但是在用户点击图片后，我想在图片上写上文字然后保存。
【问题讨论】：
标签： android
【发布时间】：2016-09-19 21:52:23
【问题描述】：
你可以把一个EditText写进去，写完之后，你先把它转换成Bitmap，比如：
Bitmap bmp = Bitmap.createBitmap(mEditText.getDrawingCache());
现在您可以像这样将创建的图像 bmp 添加到原始图像：
电话：Bitmap combined = combineImages(bgBitmap,bmp);
public Bitmap combineImages(Bitmap background, Bitmap foreground) {
int width = 0, height = 0;
Bitmap cs;
width = getWindowManager().getDefaultDisplay().getWidth();
height = getWindowManager().getDefaultDisplay().getHeight();
cs = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas comboImage = new Canvas(cs);
background = Bitmap.createScaledBitmap(background, width, height, true);
comboImage.drawBitmap(background, 0, 0, null);
comboImage.drawBitmap(foreground, matrix, null);
return cs;
}
【讨论】：
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天才，我永远不会有那样的。加油！
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如果我们将textview（前景）动态放在一个视图上（宽度和高度小于Sd中的原始图像），然后使用原始图像'背景'（背景=位图......），添加文字位置改变。如何保持位置？！
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矩阵值应该是多少？
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确保设置editText.setDrawingCacheEnabled(true) 否则editText.getDrawingCache() 始终为null
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矩阵是绘制前景的起点，可以用0,0代替矩阵
您必须实现一个允许用户在其上绘图的画布，然后将该画布的背景设置为该特定图像。这只是一个猜测，但它在某个地方。
【讨论】：
让我们帮助你.. 首先，您必须使用画布进行绘图。创建一个扩展 ImageView 的自定义视图。这是onDraw函数的帮助代码..：
@Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
mIcon.setBounds(0, 0, mIcon.getMinimumWidth(),
mIcon.getMinimumHeight());
canvas.translate(mPosX, mPosY);
canvas.scale(mScaleFactor, mScaleFactor, canvas.getWidth() * 0.5f,
canvas.getWidth() * 0.5f);
mIcon.draw(canvas);
rect = canvas.getClipBounds();
for (Path path : listPath) {
canvas.drawPath(path, paint);
}
}
现在是 onTouch：
@Override
public boolean onTouchEvent(MotionEvent ev) {
// Let the ScaleGestureDetector inspect all events.
mScaleDetector.onTouchEvent(ev);
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
if (drawing) {
startPoint = new Point((int) ev.getX(), (int) ev.getY());
path = new Path();
float x = ev.getX() / mScaleFactor + rect.left;
float y = ev.getY() / mScaleFactor + rect.top;
path.moveTo(x, y);
path.lineTo(x, y);
mLastTouchX_1 = x;
mLastTouchY_1 = y;
}
else {
final float x = ev.getX();
final float y = ev.getY();
mLastTouchX = x;
mLastTouchY = y;
mActivePointerId = ev.getPointerId(0);
}
break;
}
case MotionEvent.ACTION_MOVE: {
if (drawing) {
float x = ev.getX() / mScaleFactor + rect.left;
float y = ev.getY() / mScaleFactor + rect.top;
path.moveTo(mLastTouchX_1, mLastTouchY_1);
path.lineTo(x, y);
mLastTouchX_1 = x;
mLastTouchY_1 = y;
}
else {
final int pointerIndex = ev
.findPointerIndex(mActivePointerId);
final float x = ev.getX(pointerIndex);
final float y = ev.getY(pointerIndex);
// Only move if the ScaleGestureDetector isn't processing a
// gesture.
if (!mScaleDetector.isInProgress()) {
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
mPosX += dx;
mPosY += dy;
invalidate();
}
mLastTouchX = x;
mLastTouchY = y;
}
break;
}
case MotionEvent.ACTION_UP: {
path_helper_1 = new Path();
path_helper_2 = new Path();
endPoint = new Point((int) ev.getX(), (int) ev.getY());
int left, top, right, bottom;
left = endPoint.x - 10;
top = endPoint.y - 10;
right = endPoint.x + ((endPoint.y / 2));
bottom = endPoint.x + ((endPoint.y / 2));
float dx, dy;
dx = endPoint.x - startPoint.x;
dy = endPoint.y - startPoint.y;
dx = dx * -1;
dy = dy * -1;
// dx = dy = 100;
double cos = 0.866 * .1;
double sin = 0.500 * .1;
PointF end1 = new PointF((float) (endPoint.x + (dx * cos + dy
* -sin)), (float) (endPoint.y + (dx * sin + dy * cos)));
PointF end2 = new PointF((float) (endPoint.x + (dx * cos + dy
* sin)), (float) (endPoint.y + (dx * -sin + dy * cos)));
// path.moveTo(endPoint.x, endPoint.y);
//
// path.lineTo(endPoint.x, endPoint.y);
//
// path.lineTo(end1.x, end1.y);
//
// path.moveTo(endPoint.x, endPoint.y);
//
// path.lineTo(end2.x, end2.y);
//
//
// listPath.add(path);
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastTouchX = ev.getX(newPointerIndex);
mLastTouchY = ev.getY(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
}
break;
}
}
invalidate();
return true;
}
如果你想实现这样的缩放功能，也可以创建一个私有类：
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScale(ScaleGestureDetector detector) {
if (zoom) {
mScaleFactor *= detector.getScaleFactor();
// Don't let the object get too small or too large.
mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 5.0f));
}
invalidate();
return true;
}
}
}
从上面的代码中汲取灵感并根据您的要求进行更改。 注意 上面的代码实现了绘图和缩放功能。如果你想在图像上添加文本，那么就像路径绘图一样，你也可以使用 canvas.drawText 在画布上绘制文本。如果您想要多个文本覆盖图像，请创建一个数组列表。
【讨论】：
在位图上添加文字：
public Bitmap drawTextToBitmap(Context gContext,
int gResId,
String gText) {
Resources resources = gContext.getResources();
float scale = resources.getDisplayMetrics().density;
Bitmap bitmap =
BitmapFactory.decodeResource(resources, gResId);
android.graphics.Bitmap.Config bitmapConfig =
bitmap.getConfig();
// set default bitmap config if none
if(bitmapConfig == null) {
bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
}
// resource bitmaps are imutable,
// so we need to convert it to mutable one
bitmap = bitmap.copy(bitmapConfig, true);
Canvas canvas = new Canvas(bitmap);
// new antialised Paint
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
// text color - #3D3D3D
paint.setColor(Color.rgb(61, 61, 61));
// text size in pixels
paint.setTextSize((int) (14 * scale));
// text shadow
paint.setShadowLayer(1f, 0f, 1f, Color.WHITE);
// draw text to the Canvas center
Rect bounds = new Rect();
paint.getTextBounds(gText, 0, gText.length(), bounds);
int x = (bitmap.getWidth() - bounds.width())/2;
int y = (bitmap.getHeight() + bounds.height())/2;
canvas.drawText(gText, x, y, paint);
return bitmap;
}
来源：http://www.skoumal.net/en/android-how-draw-text-bitmap/
在位图上添加多行文字：
public Bitmap drawMultilineTextToBitmap(Context gContext,
int gResId,
String gText) {
// prepare canvas
Resources resources = gContext.getResources();
float scale = resources.getDisplayMetrics().density;
Bitmap bitmap = BitmapFactory.decodeResource(resources, gResId);
android.graphics.Bitmap.Config bitmapConfig = bitmap.getConfig();
// set default bitmap config if none
if(bitmapConfig == null) {
bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
}
// resource bitmaps are imutable,
// so we need to convert it to mutable one
bitmap = bitmap.copy(bitmapConfig, true);
Canvas canvas = new Canvas(bitmap);
// new antialiased Paint
TextPaint paint=new TextPaint(Paint.ANTI_ALIAS_FLAG);
// text color - #3D3D3D
paint.setColor(Color.rgb(61, 61, 61));
// text size in pixels
paint.setTextSize((int) (14 * scale));
// text shadow
paint.setShadowLayer(1f, 0f, 1f, Color.WHITE);
// set text width to canvas width minus 16dp padding
int textWidth = canvas.getWidth() - (int) (16 * scale);
// init StaticLayout for text
StaticLayout textLayout = new StaticLayout(
gText, paint, textWidth, Layout.Alignment.ALIGN_CENTER, 1.0f, 0.0f, false);
// get height of multiline text
int textHeight = textLayout.getHeight();
// get position of text's top left corner
float x = (bitmap.getWidth() - textWidth)/2;
float y = (bitmap.getHeight() - textHeight)/2;
// draw text to the Canvas center
canvas.save();
canvas.translate(x, y);
textLayout.draw(canvas);
canvas.restore();
return bitmap;
}
来源：http://www.skoumal.net/en/android-drawing-multiline-text-on-bitmap/
【讨论】：