How to use

getResources

method

in

com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView

/**
 * This is a screen density aware alternative to {@link #setMaxScale(float)}; it allows you to express the maximum
 * allowed scale in terms of the minimum pixel density. This avoids the problem of 1:1 scale still being
 * too small on a high density screen. A sensible starting point is 160 - the default used by this view.
 * @param dpi Source image pixel density at maximum zoom.
 */
public final void setMinimumDpi(int dpi) {
  DisplayMetrics metrics = getResources().getDisplayMetrics();
  float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
  setMaxScale(averageDpi/dpi);
}

/**
 * A density aware alternative to {@link #setDoubleTapZoomScale(float)}; this allows you to express the scale the
 * image will zoom in to when double tapped in terms of the image pixel density. Values lower than the max scale will
 * be ignored. A sensible starting point is 160 - the default used by this view.
 * @param dpi New value for double tap gesture zoom scale.
 */
public final void setDoubleTapZoomDpi(int dpi) {
  DisplayMetrics metrics = getResources().getDisplayMetrics();
  float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
  setDoubleTapZoomScale(averageDpi/dpi);
}

/**
 * This is a screen density aware alternative to {@link #setMinScale(float)}; it allows you to express the minimum
 * allowed scale in terms of the maximum pixel density.
 * @param dpi Source image pixel density at minimum zoom.
 */
public final void setMaximumDpi(int dpi) {
  DisplayMetrics metrics = getResources().getDisplayMetrics();
  float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
  setMinScale(averageDpi / dpi);
}

/**
 * By default, image tiles are at least as high resolution as the screen. For a retina screen this may not be
 * necessary, and may increase the likelihood of an OutOfMemoryError. This method sets a DPI at which higher
 * resolution tiles should be loaded. Using a lower number will on average use less memory but result in a lower
 * quality image. 160-240dpi will usually be enough. This should be called before setting the image source,
 * because it affects which tiles get loaded. When using an untiled source image this method has no effect.
 * @param minimumTileDpi Tile loading threshold.
 */
public void setMinimumTileDpi(int minimumTileDpi) {
  DisplayMetrics metrics = getResources().getDisplayMetrics();
  float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
  this.minimumTileDpi = (int)Math.min(averageDpi, minimumTileDpi);
  if (isReady()) {
    reset(false);
    invalidate();
  }
}

public SubsamplingScaleImageView(Context context, AttributeSet attr) {
  super(context, attr);
  density = getResources().getDisplayMetrics().density;
  setMinimumDpi(160);
  setDoubleTapZoomDpi(160);

DisplayMetrics metrics = getResources().getDisplayMetrics();
float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
scale = (minimumTileDpi/averageDpi) * scale;

/**
 * A density aware alternative to {@link #setDoubleTapZoomScale(float)}; this allows you to express the scale the
 * image will zoom in to when double tapped in terms of the image pixel density. Values lower than the max scale will
 * be ignored. A sensible starting point is 160 - the default used by this view.
 * @param dpi New value for double tap gesture zoom scale.
 */
public final void setDoubleTapZoomDpi(int dpi) {
  DisplayMetrics metrics = getResources().getDisplayMetrics();
  float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
  setDoubleTapZoomScale(averageDpi/dpi);
}

/**
 * This is a screen density aware alternative to {@link #setMaxScale(float)}; it allows you to express the maximum
 * allowed scale in terms of the minimum pixel density. This avoids the problem of 1:1 scale still being
 * too small on a high density screen. A sensible starting point is 160 - the default used by this view.
 * @param dpi Source image pixel density at maximum zoom.
 */
public final void setMinimumDpi(int dpi) {
  DisplayMetrics metrics = getResources().getDisplayMetrics();
  float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
  setMaxScale(averageDpi/dpi);
}

/**
 * This is a screen density aware alternative to {@link #setMinScale(float)}; it allows you to express the minimum
 * allowed scale in terms of the maximum pixel density.
 * @param dpi Source image pixel density at minimum zoom.
 */
public final void setMaximumDpi(int dpi) {
  DisplayMetrics metrics = getResources().getDisplayMetrics();
  float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
  setMinScale(averageDpi / dpi);
}

/**
 * By default, image tiles are at least as high resolution as the screen. For a retina screen this may not be
 * necessary, and may increase the likelihood of an OutOfMemoryError. This method sets a DPI at which higher
 * resolution tiles should be loaded. Using a lower number will on average use less memory but result in a lower
 * quality image. 160-240dpi will usually be enough. This should be called before setting the image source,
 * because it affects which tiles get loaded. When using an untiled source image this method has no effect.
 * @param minimumTileDpi Tile loading threshold.
 */
public void setMinimumTileDpi(int minimumTileDpi) {
  DisplayMetrics metrics = getResources().getDisplayMetrics();
  float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
  this.minimumTileDpi = (int)Math.min(averageDpi, minimumTileDpi);
  if (isReady()) {
    reset(false);
    invalidate();
  }
}

public SubsamplingScaleImageView(Context context, AttributeSet attr) {
  super(context, attr);
  density = getResources().getDisplayMetrics().density;
  setMinimumDpi(160);
  setDoubleTapZoomDpi(160);

DisplayMetrics metrics = getResources().getDisplayMetrics();
float averageDpi = (metrics.xdpi + metrics.ydpi)/2;
scale = (minimumTileDpi/averageDpi) * scale;