adding option to display pdf in dual mode and the isLandscape property

Author: Arnaud Delubac

android-pdf-viewer/src/main/java/com/github/barteksc/pdfviewer/DecodingAsyncTask.java

@@ -52,8 +52,8 @@ protected Throwable doInBackground(Void... params) {
             if (pdfView != null) {
                 PdfDocument pdfDocument = docSource.createDocument(pdfView.getContext(), pdfiumCore, password);
                 pdfFile = new PdfFile(pdfiumCore, pdfDocument, pdfView.getPageFitPolicy(), getViewSize(pdfView),
-                        userPages, pdfView.isSwipeVertical(), pdfView.getSpacingPx(), pdfView.isAutoSpacingEnabled(),
-                        pdfView.isFitEachPage());
+                        userPages, pdfView.isOnDualPageMode(),  pdfView.isSwipeVertical(), pdfView.getSpacingPx(), pdfView.isAutoSpacingEnabled(),
+                        pdfView.isFitEachPage(), pdfView.isOnLandscapeOrientation());
                 return null;
             } else {
                 return new NullPointerException("pdfView == null");

android-pdf-viewer/src/main/java/com/github/barteksc/pdfviewer/PDFView.java

@@ -176,6 +176,10 @@ enum ScrollDir {
 
     private int defaultPage = 0;
 
+    private boolean dualPageMode = false;
+
+    private boolean isLandscapeOrientation = false;
+
     /** True if should scroll through pages vertically instead of horizontally */
     private boolean swipeVertical = true;
 
@@ -1179,6 +1183,18 @@ public boolean isBestQuality() {
         return bestQuality;
     }
 
+    public boolean isOnDualPageMode() {
+        return dualPageMode;
+    }
+
+    public boolean isOnLandscapeOrientation() { return isLandscapeOrientation; }
+
+    public void setLandscapeOrientation(boolean landscapeOrientation) {this.isLandscapeOrientation = landscapeOrientation; }
+
+    public void setDualPageMode(boolean dualPageMode) {
+        this.dualPageMode = dualPageMode;
+    }
+
     public boolean isSwipeVertical() {
         return swipeVertical;
     }
@@ -1353,6 +1369,10 @@ public class Configurator {
 
         private int defaultPage = 0;
 
+        private boolean landscapeOrientation = false;
+
+        private boolean dualPageMode = false;
+
         private boolean swipeHorizontal = false;
 
         private boolean annotationRendering = false;
@@ -1461,6 +1481,16 @@ public Configurator defaultPage(int defaultPage) {
             return this;
         }
 
+        public Configurator landscapeOrientation(boolean landscapeOrientation) {
+            this.landscapeOrientation = landscapeOrientation;
+            return this;
+        }
+
+        public Configurator dualPageMode(boolean dualPageMode) {
+            this.dualPageMode = dualPageMode;
+            return this;
+        }
+
         public Configurator swipeHorizontal(boolean swipeHorizontal) {
             this.swipeHorizontal = swipeHorizontal;
             return this;
@@ -1542,6 +1572,8 @@ public void load() {
             PDFView.this.setNightMode(nightMode);
             PDFView.this.enableDoubletap(enableDoubletap);
             PDFView.this.setDefaultPage(defaultPage);
+            PDFView.this.setLandscapeOrientation(landscapeOrientation);
+            PDFView.this.setDualPageMode(dualPageMode);
             PDFView.this.setSwipeVertical(!swipeHorizontal);
             PDFView.this.enableAnnotationRendering(annotationRendering);
             PDFView.this.setScrollHandle(scrollHandle);

android-pdf-viewer/src/main/java/com/github/barteksc/pdfviewer/PdfFile.java

@@ -51,6 +51,8 @@ class PdfFile {
     private SizeF maxHeightPageSize = new SizeF(0, 0);
     /** Scaled page with maximum width */
     private SizeF maxWidthPageSize = new SizeF(0, 0);
+    /** True if dualPageMode is on*/
+    private boolean showTwoPages;
     /** True if scrolling is vertical, else it's horizontal */
     private boolean isVertical;
     /** Fixed spacing between pages in pixels */
@@ -69,14 +71,17 @@ class PdfFile {
      * else the largest page fits and other pages scale relatively
      */
     private final boolean fitEachPage;
+
+    private final boolean isLandscape;
     /**
      * The pages the user want to display in order
      * (ex: 0, 2, 2, 8, 8, 1, 1, 1)
      */
     private int[] originalUserPages;
 
     PdfFile(PdfiumCore pdfiumCore, PdfDocument pdfDocument, FitPolicy pageFitPolicy, Size viewSize, int[] originalUserPages,
-            boolean isVertical, int spacing, boolean autoSpacing, boolean fitEachPage) {
+            boolean showTwoPages, boolean isVertical, int spacing, boolean autoSpacing, boolean fitEachPage, boolean isLandscape) {
+        this.showTwoPages = showTwoPages;
         this.pdfiumCore = pdfiumCore;
         this.pdfDocument = pdfDocument;
         this.pageFitPolicy = pageFitPolicy;
@@ -85,6 +90,7 @@ class PdfFile {
         this.spacingPx = spacing;
         this.autoSpacing = autoSpacing;
         this.fitEachPage = fitEachPage;
+        this.isLandscape = isLandscape;
         setup(viewSize);
     }
 
@@ -122,7 +128,7 @@ public void recalculatePageSizes(Size viewSize) {
         maxHeightPageSize = calculator.getOptimalMaxHeightPageSize();
 
         for (Size size : originalPageSizes) {
-            pageSizes.add(calculator.calculate(size));
+            pageSizes.add(calculator.calculate(size, showTwoPages, isLandscape));
         }
         if (autoSpacing) {
             prepareAutoSpacing(viewSize);

android-pdf-viewer/src/main/java/com/github/barteksc/pdfviewer/scroll/DefaultScrollHandle.java

@@ -149,7 +149,11 @@ private void calculateMiddle() {
             pos = getY();
             viewSize = getHeight();
             pdfViewSize = pdfView.getHeight();
-        } else {
+        } else if (pdfView.isOnDualPageMode()){
+            pos = getX();
+            viewSize = getWidth() / 2;
+            pdfViewSize = pdfView.getWidth() / 2;
+        } else  {
             pos = getX();
             viewSize = getWidth();
             pdfViewSize = pdfView.getWidth();

android-pdf-viewer/src/main/java/com/github/barteksc/pdfviewer/util/PageSizeCalculator.java

@@ -15,6 +15,9 @@
  */
 package com.github.barteksc.pdfviewer.util;
 
+import android.app.Activity;
+import android.util.Log;
+import android.content.pm.ActivityInfo;
 import com.shockwave.pdfium.util.Size;
 import com.shockwave.pdfium.util.SizeF;
 
@@ -40,11 +43,16 @@ public PageSizeCalculator(FitPolicy fitPolicy, Size originalMaxWidthPageSize, Si
         calculateMaxPages();
     }
 
-    public SizeF calculate(Size pageSize) {
+    public SizeF calculate(Size pageSize, boolean showTwoPages, boolean isLandscape) {
         if (pageSize.getWidth() <= 0 || pageSize.getHeight() <= 0) {
             return new SizeF(0, 0);
         }
-        float maxWidth = fitEachPage ? viewSize.getWidth() : pageSize.getWidth() * widthRatio;
+        float maxWidth = 0;
+        if(showTwoPages && !isLandscape){
+           maxWidth = fitEachPage ? viewSize.getWidth()  : pageSize.getWidth() / 2 * widthRatio;
+        } else {
+            maxWidth = fitEachPage ? viewSize.getWidth() : pageSize.getWidth() * widthRatio;
+        }
         float maxHeight = fitEachPage ? viewSize.getHeight() : pageSize.getHeight() * heightRatio;
         switch (fitPolicy) {
             case HEIGHT:

sample/src/main/java/com/github/barteksc/sample/PDFViewActivity.java

@@ -18,6 +18,7 @@
 import android.content.ActivityNotFoundException;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.content.res.Configuration;
 import android.database.Cursor;
 import android.graphics.Color;
 import android.net.Uri;
@@ -71,6 +72,8 @@ public class PDFViewActivity extends AppCompatActivity implements OnPageChangeLi
 
     String pdfFileName;
 
+
+
     @OptionsItem(R.id.pickFile)
     void pickFile() {
         int permissionCheck = ContextCompat.checkSelfPermission(this,
@@ -112,15 +115,24 @@ void afterViews() {
     }
 
     private void displayFromAsset(String assetFileName) {
+        boolean isLandscape = false;
+        int orientation = this.getResources().getConfiguration().orientation;
+        isLandscape = orientation == Configuration.ORIENTATION_LANDSCAPE;
         pdfFileName = assetFileName;
 
         pdfView.fromAsset(SAMPLE_FILE)
                 .defaultPage(pageNumber)
                 .onPageChange(this)
                 .enableAnnotationRendering(true)
                 .onLoad(this)
+                .landscapeOrientation(isLandscape)
+                .dualPageMode(true)
                 .scrollHandle(new DefaultScrollHandle(this))
-                .spacing(10) // in dp
+                .spacing(0) // in dp
+                .enableSwipe(true)
+                .swipeHorizontal(true)
+                .pageFling(true)
+                .fitEachPage(false)
                 .onPageError(this)
                 .pageFitPolicy(FitPolicy.BOTH)
                 .load();
@@ -135,7 +147,11 @@ private void displayFromUri(Uri uri) {
                 .enableAnnotationRendering(true)
                 .onLoad(this)
                 .scrollHandle(new DefaultScrollHandle(this))
-                .spacing(10) // in dp
+                .spacing(0) // in dp
+                .dualPageMode(true)
+                .enableSwipe(true)
+                .swipeHorizontal(true)
+                .pageFling(true)
                 .onPageError(this)
                 .load();
     }