Support set camera frame position

sample/src/main/res/layout/capture_appcompat.xml

@@ -38,6 +38,7 @@
         android:layout_below="@+id/my_awesome_toolbar"
         android:layout_alignParentBottom="true"
         android:id="@+id/zxing_barcode_scanner"
+        app:zxing_framing_offset_y="100dp"
         app:zxing_use_texture_view="true"/>
 
 

sample/src/main/res/layout/capture_small.xml

@@ -33,6 +33,7 @@
         android:layout_marginTop="150dp"
         android:layout_marginBottom="150dp"
         android:id="@+id/zxing_barcode_scanner"
+        app:zxing_framing_offset_y_ratio="0.32"
         app:zxing_use_texture_view="false"
         app:zxing_preview_scaling_strategy="fitXY"/>
 

zxing-android-embedded/res/values/zxing_attrs.xml

@@ -8,6 +8,8 @@
   <declare-styleable name="zxing_camera_preview">
     <attr name="zxing_framing_rect_width" format="dimension" />
     <attr name="zxing_framing_rect_height" format="dimension" />
+    <attr name="zxing_framing_offset_y" format="dimension" />
+    <attr name="zxing_framing_offset_y_ratio" format="float" />
     <attr name="zxing_use_texture_view" format="boolean" />
     <attr name="zxing_preview_scaling_strategy" format="enum">
       <enum name="centerCrop" value="1" />

zxing-android-embedded/src/com/journeyapps/barcodescanner/CameraPreview.java

@@ -8,7 +8,6 @@
 import android.graphics.Matrix;
 import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
-import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
@@ -139,6 +138,12 @@ public interface StateListener {
     // must be smaller than 0.5;
     private double marginFraction = 0.1d;
 
+    // Frame rectangle Y axis offset
+    private int framingOffsetY;
+
+    // Frame rectangle Y axis offset percentage
+    private float framingOffsetYRatio = 0.5f;
+
     private PreviewScalingStrategy previewScalingStrategy = null;
 
     private boolean torchOn = false;
@@ -276,6 +281,13 @@ protected void initializeAttributes(AttributeSet attrs) {
             this.framingRectSize = new Size(framingRectWidth, framingRectHeight);
         }
 
+        this.framingOffsetY = styledAttributes.getDimensionPixelSize(R.styleable.zxing_camera_preview_zxing_framing_offset_y, -1);
+
+        float framingOffsetYRatio = styledAttributes.getFloat(R.styleable.zxing_camera_preview_zxing_framing_offset_y_ratio, 0.5f);
+        if (framingOffsetYRatio >= 0.0f && framingOffsetYRatio <= 1.0f) {
+            this.framingOffsetYRatio = framingOffsetYRatio;
+        }
+
         this.useTextureView = styledAttributes.getBoolean(R.styleable.zxing_camera_preview_zxing_use_texture_view, true);
 
         // See zxing_attrs.xml for the enum values
@@ -840,6 +852,14 @@ protected Rect calculateFramingRect(Rect container, Rect surface) {
             int horizontalMargin = Math.max(0, (intersection.width() - framingRectSize.width) / 2);
             int verticalMargin = Math.max(0, (intersection.height() - framingRectSize.height) / 2);
             intersection.inset(horizontalMargin, verticalMargin);
+
+            // Y axis offset
+            if (framingOffsetY == -1) {
+                intersection.offset(0, (int) ((container.height() - intersection.height()) * framingOffsetYRatio - verticalMargin));
+            } else {
+                intersection.offset(0, framingOffsetY - verticalMargin);
+            }
+
             return intersection;
         }
         // margin as 10% (default) of the smaller of width, height
@@ -849,6 +869,14 @@ protected Rect calculateFramingRect(Rect container, Rect surface) {
             // We don't want a frame that is taller than wide.
             intersection.inset(0, (intersection.height() - intersection.width()) / 2);
         }
+
+        // Y axis offset
+        if (framingOffsetY == -1) {
+            intersection.offset(0, (int) ((container.height() - intersection.height()) * (framingOffsetYRatio - 0.5f)));
+        } else {
+            intersection.offset(0, (int) (framingOffsetY - ((container.height() - intersection.height()) * 0.5f)));
+        }
+
         return intersection;
     }