Increase zoom range #84

GrapheneOS · Aug 11, 2021 · 62d0ca0 · 62d0ca0
1 parent c1e2b20
commit 62d0ca0
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Showing 4 changed files with 24 additions and 9 deletions.
diff --git a/app/src/main/assets/viewer.css b/app/src/main/assets/viewer.css
@@ -68,3 +68,17 @@ body, canvas, #padding {
 .textLayer .endOfContent.active {
     top: 0px;
 }
+
+html, body {
+  display: table;
+  height: 100%;
+  width: 100%;
+  text-align:center;
+}
+
+#content-wrapper {
+	display: flex;
+	justify-content: center; /* center horizontally */
+	align-items: center;
+	height: 100%;
+}
diff --git a/app/src/main/assets/viewer.html b/app/src/main/assets/viewer.html
@@ -7,8 +7,9 @@
         <script src="pdf.js"></script>
     </head>
     <body>
-        <div id="padding"></div>
-        <canvas id="content"></canvas>
+        <div id="content-wrapper">
+            <canvas id="content"></canvas>
+        </div>
         <div id="text" class="textLayer"></div>
         <script src="viewer.js"></script>
     </body>

diff --git a/app/src/main/assets/viewer.js b/app/src/main/assets/viewer.js
@@ -1,6 +1,5 @@
 "use strict";
 
-const padding = document.getElementById("padding");
 let pdfDoc = null;
 let pageRendering = false;
 let renderPending = false;
@@ -54,7 +53,6 @@ function display(newCanvas, zoom) {
     canvas.width = newCanvas.width;
     canvas.style.height = newCanvas.style.height;
     canvas.style.width = newCanvas.style.width;
-    padding.style.width = canvas.style.width;
     canvas.getContext("2d", { alpha: false }).drawImage(newCanvas, 0, 0);
     if (!zoom) {
         scrollTo(0, 0);
@@ -95,7 +93,7 @@ function renderPage(pageNumber, zoom, prerender, prerenderTrigger=0) {
             return;
         }
 
-        const viewport = page.getViewport({scale: newZoomRatio, rotation: orientationDegrees})
+        const viewport = page.getViewport({scale: window.screen.width / page.getViewport({scale: 1}).width * newZoomRatio, rotation: orientationDegrees})
 
         if (useRender) {
             if (newZoomRatio !== zoomRatio) {
@@ -200,7 +198,9 @@ function isTextSelected() {
 
 function updateInset() {
     const windowInsetTop = channel.getWindowInsetTop() / window.devicePixelRatio + "px";
-    padding.style.paddingTop = windowInsetTop;
+    canvas.style.paddingTop = windowInsetTop;
+    // bottom insets was added to ensure that the PDF is in center
+    canvas.style.paddingBottom = windowInsetTop;
     textLayerDiv.style.top = windowInsetTop;
 }
 

diff --git a/app/src/main/java/org/grapheneos/pdfviewer/PdfViewer.java b/app/src/main/java/org/grapheneos/pdfviewer/PdfViewer.java
@@ -76,8 +76,8 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
         "usb 'none'; " +
         "vr 'none'";
 
-    private static final float MIN_ZOOM_RATIO = 0.5f;
-    private static final float MAX_ZOOM_RATIO = 1.5f;
+    private static final float MIN_ZOOM_RATIO = 0.9f;
+    private static final float MAX_ZOOM_RATIO = 3f;
     private static final int ALPHA_LOW = 130;
     private static final int ALPHA_HIGH = 255;
     private static final int ACTION_OPEN_DOCUMENT_REQUEST_CODE = 1;
@@ -88,7 +88,7 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
     private Uri mUri;
     public int mPage;
     public int mNumPages;
-    private float mZoomRatio = 1f;
+    private float mZoomRatio = MIN_ZOOM_RATIO;
     private int mDocumentOrientationDegrees;
     private int mDocumentState;
     private int windowInsetTop;