Java tutorial
/* * Copyright (C) 2008 ZXing authors * Copyright 2011 Robert Theis * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.example.firstocr; import android.content.Context; import android.content.res.Resources; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Paint.Align; import android.graphics.Paint.Style; import android.graphics.Point; import android.graphics.Rect; import android.support.v4.content.ContextCompat; import android.util.AttributeSet; import android.view.View; import com.example.firstocr.camera.CameraManager; import java.util.List; /** * This view is overlaid on top of the camera preview. It adds the viewfinder rectangle and partial * transparency outside it, as well as the result text. * * The code for this class was adapted from the ZXing project: http://code.google.com/p/zxing */ public final class ViewfinderView extends View { //private static final long ANIMATION_DELAY = 80L; /** Flag to draw boxes representing the results from TessBaseAPI::GetRegions(). */ static final boolean DRAW_REGION_BOXES = false; /** Flag to draw boxes representing the results from TessBaseAPI::GetTextlines(). */ static final boolean DRAW_TEXTLINE_BOXES = true; /** Flag to draw boxes representing the results from TessBaseAPI::GetStrips(). */ static final boolean DRAW_STRIP_BOXES = false; /** Flag to draw boxes representing the results from TessBaseAPI::GetWords(). */ static final boolean DRAW_WORD_BOXES = true; /** Flag to draw word text with a background varying from transparent to opaque. */ static final boolean DRAW_TRANSPARENT_WORD_BACKGROUNDS = false; /** Flag to draw boxes representing the results from TessBaseAPI::GetCharacters(). */ static final boolean DRAW_CHARACTER_BOXES = false; /** Flag to draw the text of words within their respective boxes from TessBaseAPI::GetWords(). */ static final boolean DRAW_WORD_TEXT = false; /** Flag to draw each character in its respective box from TessBaseAPI::GetCharacters(). */ static final boolean DRAW_CHARACTER_TEXT = false; private CameraManager cameraManager; private final Paint paint; private final int maskColor; private final int frameColor; private final int cornerColor; private OcrResultText resultText; private String[] words; private List<Rect> regionBoundingBoxes; private List<Rect> textlineBoundingBoxes; private List<Rect> stripBoundingBoxes; private List<Rect> wordBoundingBoxes; private List<Rect> characterBoundingBoxes; // Rect bounds; private Rect previewFrame; private Rect rect; // This constructor is used when the class is built from an XML resource. public ViewfinderView(Context context, AttributeSet attrs) { super(context, attrs); // Initialize these once for performance rather than calling them every time in onDraw(). paint = new Paint(Paint.ANTI_ALIAS_FLAG); Resources resources = getResources(); //maskColor = 0x60000000; //frameColor = 0xffd6d6d6; //cornerColor = 0xffffffff; maskColor = ContextCompat.getColor(context, R.color.viewfinder_mask); frameColor = ContextCompat.getColor(context, R.color.viewfinder_frame); cornerColor = ContextCompat.getColor(context, R.color.viewfinder_corners); /*maskColor = resources.getColor(R.color.viewfinder_mask); frameColor = resources.getColor(R.color.viewfinder_frame); cornerColor = resources.getColor(R.color.viewfinder_corners); */ // bounds = new Rect(); previewFrame = new Rect(); rect = new Rect(); } public void setCameraManager(CameraManager cameraManager) { this.cameraManager = cameraManager; } @SuppressWarnings("unused") @Override public void onDraw(Canvas canvas) { Rect frame = cameraManager.getFramingRect(); if (frame == null) { return; } int width = canvas.getWidth(); int height = canvas.getHeight(); // Draw the exterior (i.e. outside the framing rect) darkened paint.setColor(maskColor); canvas.drawRect(0, 0, width, frame.top, paint); canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint); canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint); canvas.drawRect(0, frame.bottom + 1, width, height, paint); // If we have an OCR result, overlay its information on the viewfinder. if (resultText != null) { // Only draw text/bounding boxes on viewfinder if it hasn't been resized since the OCR was requested. Point bitmapSize = resultText.getBitmapDimensions(); previewFrame = cameraManager.getFramingRectInPreview(); if (bitmapSize.x == previewFrame.width() && bitmapSize.y == previewFrame.height()) { float scaleX = frame.width() / (float) previewFrame.width(); float scaleY = frame.height() / (float) previewFrame.height(); if (DRAW_REGION_BOXES) { regionBoundingBoxes = resultText.getRegionBoundingBoxes(); for (int i = 0; i < regionBoundingBoxes.size(); i++) { paint.setAlpha(0xA0); paint.setColor(Color.MAGENTA); paint.setStyle(Style.STROKE); paint.setStrokeWidth(1); rect = regionBoundingBoxes.get(i); canvas.drawRect(frame.left + rect.left * scaleX, frame.top + rect.top * scaleY, frame.left + rect.right * scaleX, frame.top + rect.bottom * scaleY, paint); } } if (DRAW_TEXTLINE_BOXES) { // Draw each textline textlineBoundingBoxes = resultText.getTextlineBoundingBoxes(); paint.setAlpha(0xA0); paint.setColor(Color.RED); paint.setStyle(Style.STROKE); paint.setStrokeWidth(1); for (int i = 0; i < textlineBoundingBoxes.size(); i++) { rect = textlineBoundingBoxes.get(i); canvas.drawRect(frame.left + rect.left * scaleX, frame.top + rect.top * scaleY, frame.left + rect.right * scaleX, frame.top + rect.bottom * scaleY, paint); } } if (DRAW_STRIP_BOXES) { stripBoundingBoxes = resultText.getStripBoundingBoxes(); paint.setAlpha(0xFF); paint.setColor(Color.YELLOW); paint.setStyle(Style.STROKE); paint.setStrokeWidth(1); for (int i = 0; i < stripBoundingBoxes.size(); i++) { rect = stripBoundingBoxes.get(i); canvas.drawRect(frame.left + rect.left * scaleX, frame.top + rect.top * scaleY, frame.left + rect.right * scaleX, frame.top + rect.bottom * scaleY, paint); } } if (DRAW_WORD_BOXES || DRAW_WORD_TEXT) { // Split the text into words wordBoundingBoxes = resultText.getWordBoundingBoxes(); // for (String w : words) { // Log.e("ViewfinderView", "word: " + w); // } //Log.d("ViewfinderView", "There are " + words.length + " words in the string array."); //Log.d("ViewfinderView", "There are " + wordBoundingBoxes.size() + " words with bounding boxes."); } if (DRAW_WORD_BOXES) { paint.setAlpha(0xFF); paint.setColor(0xFF00CCFF); paint.setStyle(Style.STROKE); paint.setStrokeWidth(1); for (int i = 0; i < wordBoundingBoxes.size(); i++) { // Draw a bounding box around the word rect = wordBoundingBoxes.get(i); canvas.drawRect(frame.left + rect.left * scaleX, frame.top + rect.top * scaleY, frame.left + rect.right * scaleX, frame.top + rect.bottom * scaleY, paint); } } if (DRAW_WORD_TEXT) { words = resultText.getText().replace("\n", " ").split(" "); int[] wordConfidences = resultText.getWordConfidences(); for (int i = 0; i < wordBoundingBoxes.size(); i++) { boolean isWordBlank = true; try { if (!words[i].equals("")) { isWordBlank = false; } } catch (ArrayIndexOutOfBoundsException e) { e.printStackTrace(); } // Only draw if word has characters if (!isWordBlank) { // Draw a white background around each word rect = wordBoundingBoxes.get(i); paint.setColor(Color.WHITE); paint.setStyle(Style.FILL); if (DRAW_TRANSPARENT_WORD_BACKGROUNDS) { // Higher confidence = more opaque, less transparent background paint.setAlpha(wordConfidences[i] * 255 / 100); } else { paint.setAlpha(255); } canvas.drawRect(frame.left + rect.left * scaleX, frame.top + rect.top * scaleY, frame.left + rect.right * scaleX, frame.top + rect.bottom * scaleY, paint); // Draw the word in black text paint.setColor(Color.BLACK); paint.setAlpha(0xFF); paint.setAntiAlias(true); paint.setTextAlign(Align.LEFT); // Adjust text size to fill rect paint.setTextSize(100); paint.setTextScaleX(1.0f); // ask the paint for the bounding rect if it were to draw this text Rect bounds = new Rect(); paint.getTextBounds(words[i], 0, words[i].length(), bounds); // get the height that would have been produced int h = bounds.bottom - bounds.top; // figure out what textSize setting would create that height of text float size = (((float) (rect.height()) / h) * 100f); // and set it into the paint paint.setTextSize(size); // Now set the scale. // do calculation with scale of 1.0 (no scale) paint.setTextScaleX(1.0f); // ask the paint for the bounding rect if it were to draw this text. paint.getTextBounds(words[i], 0, words[i].length(), bounds); // determine the width int w = bounds.right - bounds.left; // calculate the baseline to use so that the entire text is visible including the descenders int text_h = bounds.bottom - bounds.top; int baseline = bounds.bottom + ((rect.height() - text_h) / 2); // determine how much to scale the width to fit the view float xscale = ((float) (rect.width())) / w; // set the scale for the text paint paint.setTextScaleX(xscale); canvas.drawText(words[i], frame.left + rect.left * scaleX, frame.top + rect.bottom * scaleY - baseline, paint); } } } // if (DRAW_CHARACTER_BOXES || DRAW_CHARACTER_TEXT) { // characterBoundingBoxes = resultText.getCharacterBoundingBoxes(); // } // // if (DRAW_CHARACTER_BOXES) { // // Draw bounding boxes around each character // paint.setAlpha(0xA0); // paint.setColor(0xFF00FF00); // paint.setStyle(Style.STROKE); // paint.setStrokeWidth(1); // for (int c = 0; c < characterBoundingBoxes.size(); c++) { // Rect characterRect = characterBoundingBoxes.get(c); // canvas.drawRect(frame.left + characterRect.left * scaleX, // frame.top + characterRect.top * scaleY, // frame.left + characterRect.right * scaleX, // frame.top + characterRect.bottom * scaleY, paint); // } // } // // if (DRAW_CHARACTER_TEXT) { // // Draw letters individually // for (int i = 0; i < characterBoundingBoxes.size(); i++) { // Rect r = characterBoundingBoxes.get(i); // // // Draw a white background for every letter // int meanConfidence = resultText.getMeanConfidence(); // paint.setColor(Color.WHITE); // paint.setAlpha(meanConfidence * (255 / 100)); // paint.setStyle(Style.FILL); // canvas.drawRect(frame.left + r.left * scaleX, // frame.top + r.top * scaleY, // frame.left + r.right * scaleX, // frame.top + r.bottom * scaleY, paint); // // // Draw each letter, in black // paint.setColor(Color.BLACK); // paint.setAlpha(0xFF); // paint.setAntiAlias(true); // paint.setTextAlign(Align.LEFT); // String letter = ""; // try { // char c = resultText.getText().replace("\n","").replace(" ", "").charAt(i); // letter = Character.toString(c); // // if (!letter.equals("-") && !letter.equals("_")) { // // // Adjust text size to fill rect // paint.setTextSize(100); // paint.setTextScaleX(1.0f); // // // ask the paint for the bounding rect if it were to draw this text // Rect bounds = new Rect(); // paint.getTextBounds(letter, 0, letter.length(), bounds); // // // get the height that would have been produced // int h = bounds.bottom - bounds.top; // // // figure out what textSize setting would create that height of text // float size = (((float)(r.height())/h)*100f); // // // and set it into the paint // paint.setTextSize(size); // // // Draw the text as is. We don't really need to set the text scale, because the dimensions // // of the Rect should already be suited for drawing our letter. // canvas.drawText(letter, frame.left + r.left * scaleX, frame.top + r.bottom * scaleY, paint); // } // } catch (StringIndexOutOfBoundsException e) { // e.printStackTrace(); // } catch (Exception e) { // e.printStackTrace(); // } // } // } } } // Draw a two pixel solid border inside the framing rect paint.setAlpha(0); paint.setStyle(Style.FILL); paint.setColor(frameColor); canvas.drawRect(frame.left, frame.top, frame.right + 1, frame.top + 2, paint); canvas.drawRect(frame.left, frame.top + 2, frame.left + 2, frame.bottom - 1, paint); canvas.drawRect(frame.right - 1, frame.top, frame.right + 1, frame.bottom - 1, paint); canvas.drawRect(frame.left, frame.bottom - 1, frame.right + 1, frame.bottom + 1, paint); // Draw the framing rect corner UI elements paint.setColor(cornerColor); canvas.drawRect(frame.left - 15, frame.top - 15, frame.left + 15, frame.top, paint); canvas.drawRect(frame.left - 15, frame.top, frame.left, frame.top + 15, paint); canvas.drawRect(frame.right - 15, frame.top - 15, frame.right + 15, frame.top, paint); canvas.drawRect(frame.right, frame.top - 15, frame.right + 15, frame.top + 15, paint); canvas.drawRect(frame.left - 15, frame.bottom, frame.left + 15, frame.bottom + 15, paint); canvas.drawRect(frame.left - 15, frame.bottom - 15, frame.left, frame.bottom, paint); canvas.drawRect(frame.right - 15, frame.bottom, frame.right + 15, frame.bottom + 15, paint); canvas.drawRect(frame.right, frame.bottom - 15, frame.right + 15, frame.bottom + 15, paint); // Request another update at the animation interval, but don't repaint the entire viewfinder mask. //postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top, frame.right, frame.bottom); } public void drawViewfinder() { invalidate(); } /** * Adds the given OCR results for drawing to the view. * * @param text Object containing OCR-derived text and corresponding data. */ public void addResultText(OcrResultText text) { resultText = text; } /** * Nullifies OCR text to remove it at the next onDraw() drawing. */ public void removeResultText() { resultText = null; } }