/**
* Copyright (c) 2014, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.facebook.csslayout;
import com.taobao.luaview.annotations.Nullable;
import java.util.Arrays;
/**
* Class representing CSS spacing (padding, margin, and borders). This is mostly necessary to
* properly implement interactions and updates for properties like margin, marginLeft, and
* marginHorizontal.
*/
public class Spacing {
/**
* Spacing type that represents the left direction. E.g. {@code marginLeft}.
*/
public static final int LEFT = 0;
/**
* Spacing type that represents the top direction. E.g. {@code marginTop}.
*/
public static final int TOP = 1;
/**
* Spacing type that represents the right direction. E.g. {@code marginRight}.
*/
public static final int RIGHT = 2;
/**
* Spacing type that represents the bottom direction. E.g. {@code marginBottom}.
*/
public static final int BOTTOM = 3;
/**
* Spacing type that represents vertical direction (top and bottom). E.g. {@code marginVertical}.
*/
public static final int VERTICAL = 4;
/**
* Spacing type that represents horizontal direction (left and right). E.g.
* {@code marginHorizontal}.
*/
public static final int HORIZONTAL = 5;
/**
* Spacing type that represents start direction e.g. left in left-to-right, right in right-to-left.
*/
public static final int START = 6;
/**
* Spacing type that represents end direction e.g. right in left-to-right, left in right-to-left.
*/
public static final int END = 7;
/**
* Spacing type that represents all directions (left, top, right, bottom). E.g. {@code margin}.
*/
public static final int ALL = 8;
private static final int[] sFlagsMap = {
1, /*LEFT*/
2, /*TOP*/
4, /*RIGHT*/
8, /*BOTTOM*/
16, /*VERTICAL*/
32, /*HORIZONTAL*/
64, /*START*/
128, /*END*/
256, /*ALL*/
};
private final float[] mSpacing = newFullSpacingArray();
@Nullable private float[] mDefaultSpacing = null;
private int mValueFlags = 0;
private boolean mHasAliasesSet;
/**
* Set a spacing value.
*
* @param spacingType one of {@link #LEFT}, {@link #TOP}, {@link #RIGHT}, {@link #BOTTOM},
* {@link #VERTICAL}, {@link #HORIZONTAL}, {@link #ALL}
* @param value the value for this direction
* @return {@code true} if the spacing has changed, or {@code false} if the same value was already
* set
*/
public boolean set(int spacingType, float value) {
if (!FloatUtil.floatsEqual(mSpacing[spacingType], value)) {
mSpacing[spacingType] = value;
if (CSSConstants.isUndefined(value)) {
mValueFlags &= ~sFlagsMap[spacingType];
} else {
mValueFlags |= sFlagsMap[spacingType];
}
mHasAliasesSet =
(mValueFlags & sFlagsMap[ALL]) != 0 ||
(mValueFlags & sFlagsMap[VERTICAL]) != 0 ||
(mValueFlags & sFlagsMap[HORIZONTAL]) != 0;
return true;
}
return false;
}
/**
* Set a default spacing value. This is used as a fallback when no spacing has been set for a
* particular direction.
*
* @param spacingType one of {@link #LEFT}, {@link #TOP}, {@link #RIGHT}, {@link #BOTTOM}
* @param value the default value for this direction
* @return
*/
public boolean setDefault(int spacingType, float value) {
if (mDefaultSpacing == null) {
mDefaultSpacing = newSpacingResultArray();
}
if (!FloatUtil.floatsEqual(mDefaultSpacing[spacingType], value)) {
mDefaultSpacing[spacingType] = value;
return true;
}
return false;
}
/**
* Get the spacing for a direction. This takes into account any default values that have been set.
*
* @param spacingType one of {@link #LEFT}, {@link #TOP}, {@link #RIGHT}, {@link #BOTTOM}
*/
public float get(int spacingType) {
float defaultValue = (mDefaultSpacing != null)
? mDefaultSpacing[spacingType]
: (spacingType == START || spacingType == END ? CSSConstants.UNDEFINED : 0);
if (mValueFlags == 0) {
return defaultValue;
}
if ((mValueFlags & sFlagsMap[spacingType]) != 0) {
return mSpacing[spacingType];
}
if (mHasAliasesSet) {
int secondType = spacingType == TOP || spacingType == BOTTOM ? VERTICAL : HORIZONTAL;
if ((mValueFlags & sFlagsMap[secondType]) != 0) {
return mSpacing[secondType];
} else if ((mValueFlags & sFlagsMap[ALL]) != 0) {
return mSpacing[ALL];
}
}
return defaultValue;
}
/**
* Get the raw value (that was set using {@link #set(int, float)}), without taking into account
* any default values.
*
* @param spacingType one of {@link #LEFT}, {@link #TOP}, {@link #RIGHT}, {@link #BOTTOM},
* {@link #VERTICAL}, {@link #HORIZONTAL}, {@link #ALL}
*/
public float getRaw(int spacingType) {
return mSpacing[spacingType];
}
/**
* Resets the spacing instance to its default state. This method is meant to be used when
* recycling {@link Spacing} instances.
*/
void reset() {
Arrays.fill(mSpacing, CSSConstants.UNDEFINED);
mDefaultSpacing = null;
mHasAliasesSet = false;
mValueFlags = 0;
}
/**
* Try to get start value and fallback to given type if not defined. This is used privately
* by the layout engine as a more efficient way to fetch direction-aware values by
* avoid extra method invocations.
*/
float getWithFallback(int spacingType, int fallbackType) {
return
(mValueFlags & sFlagsMap[spacingType]) != 0
? mSpacing[spacingType]
: get(fallbackType);
}
private static float[] newFullSpacingArray() {
return new float[] {
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
};
}
private static float[] newSpacingResultArray() {
return newSpacingResultArray(0);
}
private static float[] newSpacingResultArray(float defaultValue) {
return new float[] {
defaultValue,
defaultValue,
defaultValue,
defaultValue,
defaultValue,
defaultValue,
CSSConstants.UNDEFINED,
CSSConstants.UNDEFINED,
defaultValue,
};
}
}