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/* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.geckoview;
import androidx.annotation.AnyThread;
import androidx.annotation.IntDef;
import androidx.annotation.NonNull;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
/**
* ScreenLength is a class that represents a length on the screen using different units. The default
* unit is a pixel. However lengths may be also represented by a dimension of the visual viewport or
* of the full scroll size of the root document.
*/
public class ScreenLength {
@Retention(RetentionPolicy.SOURCE)
@IntDef({PIXEL, VISUAL_VIEWPORT_WIDTH, VISUAL_VIEWPORT_HEIGHT, DOCUMENT_WIDTH, DOCUMENT_HEIGHT})
public @interface ScreenLengthType {}
/** Pixel units. */
public static final int PIXEL = 0;
/**
* Units are in visual viewport width. If the visual viewport is 100 pixels wide, then a value of
* 2.0 would represent a length of 200 pixels.
*
* @see <a href="https://developer.mozilla.org/en-US/docs/Glossary/Visual_Viewport">MDN Visual
* Viewport</a>
*/
public static final int VISUAL_VIEWPORT_WIDTH = 1;
/**
* Units are in visual viewport height. If the visual viewport is 100 pixels high, then a value of
* 2.0 would represent a length of 200 pixels.
*
* @see <a href="https://developer.mozilla.org/en-US/docs/Glossary/Visual_Viewport">MDN Visual
* Viewport</a>
*/
public static final int VISUAL_VIEWPORT_HEIGHT = 2;
/**
* Units represent the entire scrollable documents width. If the document is 1000 pixels wide then
* a value of 1.0 would represent 1000 pixels.
*/
public static final int DOCUMENT_WIDTH = 3;
/**
* Units represent the entire scrollable documents height. If the document is 1000 pixels tall
* then a value of 1.0 would represent 1000 pixels.
*/
public static final int DOCUMENT_HEIGHT = 4;
/**
* Create a ScreenLength of zero pixels length. Type is {@link #PIXEL}.
*
* @return ScreenLength of zero length.
*/
@NonNull
@AnyThread
public static ScreenLength zero() {
return new ScreenLength(0.0, PIXEL);
}
/**
* Create a ScreenLength of zero pixels length. Type is {@link #PIXEL}. Can be used to scroll to
* the top of a page when used with PanZoomController.scrollTo()
*
* @return ScreenLength of zero length.
*/
@NonNull
@AnyThread
public static ScreenLength top() {
return zero();
}
/**
* Create a ScreenLength of the documents height. Type is {@link #DOCUMENT_HEIGHT}. Can be used to
* scroll to the bottom of a page when used with {@link PanZoomController#scrollTo(ScreenLength,
* ScreenLength)}
*
* @return ScreenLength of document height.
*/
@NonNull
@AnyThread
public static ScreenLength bottom() {
return new ScreenLength(1.0, DOCUMENT_HEIGHT);
}
/**
* Create a ScreenLength of a specific length. Type is {@link #PIXEL}.
*
* @param value Pixel length.
* @return ScreenLength of document height.
*/
@NonNull
@AnyThread
public static ScreenLength fromPixels(final double value) {
return new ScreenLength(value, PIXEL);
}
/**
* Create a ScreenLength that uses the visual viewport width as units. Type is {@link
* #VISUAL_VIEWPORT_WIDTH}. Can be used with {@link PanZoomController#scrollBy(ScreenLength,
* ScreenLength)} to scroll a value of the width of visual viewport content.
*
* @param value Factor used to calculate length. A value of 2.0 would indicate a length twice as
* long as the length of the visual viewports width.
* @return ScreenLength of specifying a length of value * visual viewport width.
*/
@NonNull
@AnyThread
public static ScreenLength fromVisualViewportWidth(final double value) {
return new ScreenLength(value, VISUAL_VIEWPORT_WIDTH);
}
/**
* Create a ScreenLength that uses the visual viewport width as units. Type is {@link
* #VISUAL_VIEWPORT_HEIGHT}. Can be used with {@link PanZoomController#scrollBy(ScreenLength,
* ScreenLength)} to scroll a value of the height of visual viewport content.
*
* @param value Factor used to calculate length. A value of 2.0 would indicate a length twice as
* long as the length of the visual viewports height.
* @return ScreenLength of specifying a length of value * visual viewport width.
*/
@NonNull
@AnyThread
public static ScreenLength fromVisualViewportHeight(final double value) {
return new ScreenLength(value, VISUAL_VIEWPORT_HEIGHT);
}
private final double mValue;
@ScreenLengthType private final int mType;
/* package */ ScreenLength(final double value, @ScreenLengthType final int type) {
mValue = value;
mType = type;
}
/**
* Returns the scalar value used to calculate length. The units of the returned valued are defined
* by what is returned by {@link #getType()}
*
* @return Scalar value of the length.
*/
@AnyThread
public double getValue() {
return mValue;
}
/**
* Returns the unit type of the length The length can be one of the following: {@link #PIXEL},
* {@link #VISUAL_VIEWPORT_WIDTH}, {@link #VISUAL_VIEWPORT_HEIGHT}, {@link #DOCUMENT_WIDTH},
* {@link #DOCUMENT_HEIGHT}
*
* @return Unit type of the length.
*/
@AnyThread
@ScreenLengthType
public int getType() {
return mType;
}
}
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