如何使用多行文本叠加图像（文本将位于canvas的中心）

我正在开发摄影应用程序，因为我用文本覆盖图像。

这是我的代码：

Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.themes11); // create a mutable bitmap with the same size as the background image's size bmOverlay = Bitmap.createBitmap(mBitmap.getWidth(), mBitmap.getHeight(), Bitmap.Config.ARGB_4444); // create a canvas on which to draw Canvas canvas = new Canvas(bmOverlay); TextPaint paint = new TextPaint(); paint.setColor(Color.RED); paint.setTextSize(40); paint.setFlags(Paint.ANTI_ALIAS_FLAG); // if the background image is defined in main.xml, omit this line canvas.drawBitmap(mBitmap, 0, 0, null); // draw the text and the point canvas.drawPoint(50, 100, paint); // canvas.drawText(InstaTextActivity.CurrentWord, 300, 200, paint); StaticLayout layout = new StaticLayout(InstaTextActivity.CurrentWord, paint, display.getHeight(), android.text.Layout.Alignment.ALIGN_NORMAL, (float) 1.0, (float) 0.0, true); canvas.translate(width / 5, height / 5); layout.draw(canvas); imageview_img.setImageBitmap(bmOverlay); 

在这段代码中，我将文本覆盖在屏幕宽度/ 2和高度/ 2上，它将显示在图像的顶部，但我希望文本居中对齐。 此外，当我写一个大文本时，它将从中心到右对齐。

看看图像，看看我想要它：

图像背景：

我想要的结果是：

Answer 1

使用以下方法测量文本的高度和宽度。 然后在canvas上绘制文本时

left = width/2 - textWidth/2
top = height/2 - textHeight/2

但是如果你需要长文本的多行文本，那将会有点棘手。

 /** * Method to get the height of the paint * * @param brush The TextPaint used to paint the text * @param text The text which needs to be measured * @return height of the text */ public static int measureTextHeight(Paint brush, String text) { Rect result = new Rect(); // Measure the text rectangle to get the height brush.getTextBounds(text, 0, text.length(), result); return result.height(); } /** * Method to get the width of the paint * * @param brush The TextPaint used to paint the text * @param text The text which needs to be measured * @return width of the text */ public static int measureTextWidth(Paint brush, String text) { Rect result = new Rect(); // Measure the text rectangle to get the height brush.getTextBounds(text, 0, text.length(), result); return result.width(); } 

Answer 2

我用这个。 为我工作。

 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/

Answer 3

这不是一个非常精细的方法（没有针对内存使用进行优化），但是完成了这项工作。 您需要修改代码，以便在字符串处拆分，保持字不变。 希望这可以帮助。

 package org.edu.abhi; import java.util.ArrayList; import java.util.List; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.os.AsyncTask; import android.util.AttributeSet; import android.util.DisplayMetrics; import android.util.Log; import android.view.View; import android.view.WindowManager; /** * @author Abhishek_Nandi * */ public class DummyUserSpace extends View { /*************************************************************************** * Calls superclass constructor. This will call {@link #init(Context)} * * @param context * The Context the view is running in, through which it can * access the current theme, resources, etc. **************************************************************************/ public DummyUserSpace(Context context) { super(context); init(context); } /*************************************************************************** * Calls superclass constructor. This will call {@link #init(Context)} * * @param context * The Context the view is running in, through which it can * access the current theme, resources, etc. * @param attrs * The attributes of the XML tag that is inflating the view. * @param defStyle * The default style to apply to this view. If 0, no style will * be applied (beyond what is included in the theme). This may * either be an attribute resource, whose value will be retrieved * from the current theme, or an explicit style resource. **************************************************************************/ public DummyUserSpace(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(context); } /*************************************************************************** * Calls superclass constructor. This will call {@link #init(Context)} * * @param context * The Context the view is running in, through which it can * access the current theme, resources, etc. * @param attrs * The attributes of the XML tag that is inflating the view. **************************************************************************/ public DummyUserSpace(Context context, AttributeSet attrs) { super(context, attrs); init(context); } /** * Width of the View */ int viewWidth = 0; /** * Height of the View */ int viewHeight = 0; /** * {@link Paint} which is used to draw {@link #text} */ Paint textPaint; /** * The text which needs to be drawn */ String text = "can be spared the burden of having to perform manual memory management. In some languages, memory for the creation of objects is implicitly allocated on the stack, or explicitly allocated and deallocated from the heap. In the latter case the responsibility of managing memory resides with the programmer. If the program does not deallocate an object, a memory leak occurs. If the program attempts to access or deallocate memory that has already been deallocated, the result is undefined and difficult to predict, and the program is likely to become unstable and/or crash. This can be partially remedied by the use of smart pointers, but these add overhead and complexity. Note that garbage collection does not prevent \"logical\" memory leaks, ie those where the memory is still referenced but never used.. o have as few implementation dependencies as possible. It is intended to let application developers \"write once, run anywhere\" (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another. Java is as of 2012 one of the most popular programming languages in use, particularly for client-server web applications, with a reported 10 million users"; /** * Common constructor routine * * @param context * The Context the view is running in. It is used to get the * density of the device */ private void init(Context context) { textPaint = new Paint(); textPaint.setColor(Color.WHITE); textPaint.setTextSize(40); textPaint.setStrokeWidth(6.0f); WindowManager manager = (WindowManager) context .getSystemService(Context.WINDOW_SERVICE); DisplayMetrics outMetrics = new DisplayMetrics(); manager.getDefaultDisplay().getMetrics(outMetrics); padding *= outMetrics.density; lineSpacing *= outMetrics.density; } /** * Split the string and compute the {@link #startY}, {@link #textHeight} * which is required for drawing the view */ private void prepareForDrawing() { viewWidth = getWidth(); viewHeight = getHeight(); if (viewHeight == 0) { return; } textHeight = Utility.measureTextHeight(textPaint, text); if (0 == textHeight) { return; } maxLines = (viewHeight - 2 * padding) / (textHeight + lineSpacing); prepareMultiLineText(textPaint, text); int noOfLines = splittedText.size(); int section = noOfLines / 2; int center = viewHeight / 2; if (noOfLines % 2 == 0) { center -= lineSpacing / 2; } else { center -= textHeight / 2; } startY = center - (section - 1) * (textHeight + lineSpacing) + lineSpacing; } /** * The starting position from where the view will start drawing */ private int startY = 0; /** * Height of the text */ private int textHeight = 0; /** * Maximum lines this view can hold */ private int maxLines = 1; /** * Padding from the view border */ private int padding = 20; /** * Spacing between each line */ private int lineSpacing = 10; private final String loadingText = "Loading.."; /* * (non-Javadoc) * * @see android.view.View#onDraw(android.graphics.Canvas) */ @Override protected void onDraw(Canvas canvas) { if (!computationComplete) { new DrawComputations().execute(); canvas.drawText( loadingText, getWidth() / 2 - Utility.measureTextWidth(textPaint, loadingText) / 2, getHeight() / 2 - Utility.measureTextHeight(textPaint, loadingText) / 2, textPaint); } else { for(int count = 0; count { /* * (non-Javadoc) * * @see android.os.AsyncTask#doInBackground(Params[]) */ @Override protected Void doInBackground(Void... params) { prepareForDrawing(); computationComplete = true; return null; } /* * (non-Javadoc) * * @see android.os.AsyncTask#onPostExecute(java.lang.Object) */ @Override protected void onPostExecute(Void result) { invalidate(); } } /** * Collection which holds the multi-line text */ private List splittedText = new ArrayList(); /** * This method is responsible for stripping {@link #text} into individual * lines in order to form the multi line text. This method can be used as a * utility. * * @param paint * The {@link Paint} which is used to draw the text * @param str * The string which needs to be stripped */ private void prepareMultiLineText(Paint paint, String str) { if (str == null || str.trim().length() == 0) return; str = str.trim(); String result = str; int boxWidth = viewWidth; try { float textWidth = paint.measureText(str) + 2 * padding; result = str; while (textWidth > boxWidth) { if (result.length() == 0) break;//keeping the entire word intact//if(result.lastIndexOf(" ")!=-1){result = result.substring(0, result.lastIndexOf(" "))}else result = result.substring(0, result.length() - 1); textWidth = paint.measureText(result) + 2 * padding; } result = result.trim(); boolean exceeded = false; if (splittedText.size() == maxLines) { exceeded = true; result = result.substring(0, result.length()-2).concat(".."); } splittedText.add(result); if (!exceeded && result.length() != str.length()) { prepareMultiLineText(textPaint, str.substring(result.length())); } } catch (Exception e) { Log.e("CustomView", "prepareMultiLineText", e); } } } // END of class // END of file 

Answer 4

你应该使用StaticLayout 。 它可以测量和绘制多行文本，处理换行，行间距，对齐等。

 StaticLayout layout = new StaticLayout("your long text", textPaint, pixelsToFitWidthTo, Layout.Alignment.ALIGN_NORMAL, 1f, 0f, true); int boxHeight = layout.getHeight(); // measure 

文本甚至可以是HTML格式的，只需将文本包装在Html.fromHtml() ：

 Html.fromHtml("your long and bold text");