| /* |
| * Copyright (C) 2006 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.view; |
| import android.graphics.Rect; |
| |
| /** |
| * Standard constants and tools for placing an object within a potentially |
| * larger container. |
| */ |
| public class Gravity |
| { |
| /** Constant indicating that no gravity has been set **/ |
| public static final int NO_GRAVITY = 0x0000; |
| |
| /** Raw bit indicating the gravity for an axis has been specified. */ |
| public static final int AXIS_SPECIFIED = 0x0001; |
| |
| /** Raw bit controlling how the left/top edge is placed. */ |
| public static final int AXIS_PULL_BEFORE = 0x0002; |
| /** Raw bit controlling how the right/bottom edge is placed. */ |
| public static final int AXIS_PULL_AFTER = 0x0004; |
| /** Raw bit controlling whether the right/bottom edge is clipped to its |
| * container, based on the gravity direction being applied. */ |
| public static final int AXIS_CLIP = 0x0008; |
| |
| /** Bits defining the horizontal axis. */ |
| public static final int AXIS_X_SHIFT = 0; |
| /** Bits defining the vertical axis. */ |
| public static final int AXIS_Y_SHIFT = 4; |
| |
| /** Push object to the top of its container, not changing its size. */ |
| public static final int TOP = (AXIS_PULL_BEFORE|AXIS_SPECIFIED)<<AXIS_Y_SHIFT; |
| /** Push object to the bottom of its container, not changing its size. */ |
| public static final int BOTTOM = (AXIS_PULL_AFTER|AXIS_SPECIFIED)<<AXIS_Y_SHIFT; |
| /** Push object to the left of its container, not changing its size. */ |
| public static final int LEFT = (AXIS_PULL_BEFORE|AXIS_SPECIFIED)<<AXIS_X_SHIFT; |
| /** Push object to the right of its container, not changing its size. */ |
| public static final int RIGHT = (AXIS_PULL_AFTER|AXIS_SPECIFIED)<<AXIS_X_SHIFT; |
| |
| /** Place object in the vertical center of its container, not changing its |
| * size. */ |
| public static final int CENTER_VERTICAL = AXIS_SPECIFIED<<AXIS_Y_SHIFT; |
| /** Grow the vertical size of the object if needed so it completely fills |
| * its container. */ |
| public static final int FILL_VERTICAL = TOP|BOTTOM; |
| |
| /** Place object in the horizontal center of its container, not changing its |
| * size. */ |
| public static final int CENTER_HORIZONTAL = AXIS_SPECIFIED<<AXIS_X_SHIFT; |
| /** Grow the horizontal size of the object if needed so it completely fills |
| * its container. */ |
| public static final int FILL_HORIZONTAL = LEFT|RIGHT; |
| |
| /** Place the object in the center of its container in both the vertical |
| * and horizontal axis, not changing its size. */ |
| public static final int CENTER = CENTER_VERTICAL|CENTER_HORIZONTAL; |
| |
| /** Grow the horizontal and vertical size of the object if needed so it |
| * completely fills its container. */ |
| public static final int FILL = FILL_VERTICAL|FILL_HORIZONTAL; |
| |
| /** Flag to clip the edges of the object to its container along the |
| * vertical axis. */ |
| public static final int CLIP_VERTICAL = AXIS_CLIP<<AXIS_Y_SHIFT; |
| |
| /** Flag to clip the edges of the object to its container along the |
| * horizontal axis. */ |
| public static final int CLIP_HORIZONTAL = AXIS_CLIP<<AXIS_X_SHIFT; |
| |
| /** Raw bit controlling whether the layout direction is relative or not (START/END instead of |
| * absolute LEFT/RIGHT). |
| */ |
| public static final int RELATIVE_LAYOUT_DIRECTION = 0x00800000; |
| |
| /** |
| * Binary mask to get the absolute horizontal gravity of a gravity. |
| */ |
| public static final int HORIZONTAL_GRAVITY_MASK = (AXIS_SPECIFIED | |
| AXIS_PULL_BEFORE | AXIS_PULL_AFTER) << AXIS_X_SHIFT; |
| /** |
| * Binary mask to get the vertical gravity of a gravity. |
| */ |
| public static final int VERTICAL_GRAVITY_MASK = (AXIS_SPECIFIED | |
| AXIS_PULL_BEFORE | AXIS_PULL_AFTER) << AXIS_Y_SHIFT; |
| |
| /** Special constant to enable clipping to an overall display along the |
| * vertical dimension. This is not applied by default by |
| * {@link #apply(int, int, int, Rect, int, int, Rect)}; you must do so |
| * yourself by calling {@link #applyDisplay}. |
| */ |
| public static final int DISPLAY_CLIP_VERTICAL = 0x10000000; |
| |
| /** Special constant to enable clipping to an overall display along the |
| * horizontal dimension. This is not applied by default by |
| * {@link #apply(int, int, int, Rect, int, int, Rect)}; you must do so |
| * yourself by calling {@link #applyDisplay}. |
| */ |
| public static final int DISPLAY_CLIP_HORIZONTAL = 0x01000000; |
| |
| /** Push object to x-axis position at the start of its container, not changing its size. */ |
| public static final int START = RELATIVE_LAYOUT_DIRECTION | LEFT; |
| |
| /** Push object to x-axis position at the end of its container, not changing its size. */ |
| public static final int END = RELATIVE_LAYOUT_DIRECTION | RIGHT; |
| |
| /** |
| * Binary mask for the horizontal gravity and script specific direction bit. |
| */ |
| public static final int RELATIVE_HORIZONTAL_GRAVITY_MASK = START | END; |
| |
| /** |
| * Apply a gravity constant to an object. This supposes that the layout direction is LTR. |
| * |
| * @param gravity The desired placement of the object, as defined by the |
| * constants in this class. |
| * @param w The horizontal size of the object. |
| * @param h The vertical size of the object. |
| * @param container The frame of the containing space, in which the object |
| * will be placed. Should be large enough to contain the |
| * width and height of the object. |
| * @param outRect Receives the computed frame of the object in its |
| * container. |
| */ |
| public static void apply(int gravity, int w, int h, Rect container, Rect outRect) { |
| apply(gravity, w, h, container, 0, 0, outRect); |
| } |
| |
| /** |
| * Apply a gravity constant to an object and take care if layout direction is RTL or not. |
| * |
| * @param gravity The desired placement of the object, as defined by the |
| * constants in this class. |
| * @param w The horizontal size of the object. |
| * @param h The vertical size of the object. |
| * @param container The frame of the containing space, in which the object |
| * will be placed. Should be large enough to contain the |
| * width and height of the object. |
| * @param outRect Receives the computed frame of the object in its |
| * container. |
| * @param layoutDirection The layout direction. |
| * |
| * @see View#LAYOUT_DIRECTION_LTR |
| * @see View#LAYOUT_DIRECTION_RTL |
| */ |
| public static void apply(int gravity, int w, int h, Rect container, |
| Rect outRect, int layoutDirection) { |
| int absGravity = getAbsoluteGravity(gravity, layoutDirection); |
| apply(absGravity, w, h, container, 0, 0, outRect); |
| } |
| |
| /** |
| * Apply a gravity constant to an object. |
| * |
| * @param gravity The desired placement of the object, as defined by the |
| * constants in this class. |
| * @param w The horizontal size of the object. |
| * @param h The vertical size of the object. |
| * @param container The frame of the containing space, in which the object |
| * will be placed. Should be large enough to contain the |
| * width and height of the object. |
| * @param xAdj Offset to apply to the X axis. If gravity is LEFT this |
| * pushes it to the right; if gravity is RIGHT it pushes it to |
| * the left; if gravity is CENTER_HORIZONTAL it pushes it to the |
| * right or left; otherwise it is ignored. |
| * @param yAdj Offset to apply to the Y axis. If gravity is TOP this pushes |
| * it down; if gravity is BOTTOM it pushes it up; if gravity is |
| * CENTER_VERTICAL it pushes it down or up; otherwise it is |
| * ignored. |
| * @param outRect Receives the computed frame of the object in its |
| * container. |
| */ |
| public static void apply(int gravity, int w, int h, Rect container, |
| int xAdj, int yAdj, Rect outRect) { |
| switch (gravity&((AXIS_PULL_BEFORE|AXIS_PULL_AFTER)<<AXIS_X_SHIFT)) { |
| case 0: |
| outRect.left = container.left |
| + ((container.right - container.left - w)/2) + xAdj; |
| outRect.right = outRect.left + w; |
| if ((gravity&(AXIS_CLIP<<AXIS_X_SHIFT)) |
| == (AXIS_CLIP<<AXIS_X_SHIFT)) { |
| if (outRect.left < container.left) { |
| outRect.left = container.left; |
| } |
| if (outRect.right > container.right) { |
| outRect.right = container.right; |
| } |
| } |
| break; |
| case AXIS_PULL_BEFORE<<AXIS_X_SHIFT: |
| outRect.left = container.left + xAdj; |
| outRect.right = outRect.left + w; |
| if ((gravity&(AXIS_CLIP<<AXIS_X_SHIFT)) |
| == (AXIS_CLIP<<AXIS_X_SHIFT)) { |
| if (outRect.right > container.right) { |
| outRect.right = container.right; |
| } |
| } |
| break; |
| case AXIS_PULL_AFTER<<AXIS_X_SHIFT: |
| outRect.right = container.right - xAdj; |
| outRect.left = outRect.right - w; |
| if ((gravity&(AXIS_CLIP<<AXIS_X_SHIFT)) |
| == (AXIS_CLIP<<AXIS_X_SHIFT)) { |
| if (outRect.left < container.left) { |
| outRect.left = container.left; |
| } |
| } |
| break; |
| default: |
| outRect.left = container.left + xAdj; |
| outRect.right = container.right + xAdj; |
| break; |
| } |
| |
| switch (gravity&((AXIS_PULL_BEFORE|AXIS_PULL_AFTER)<<AXIS_Y_SHIFT)) { |
| case 0: |
| outRect.top = container.top |
| + ((container.bottom - container.top - h)/2) + yAdj; |
| outRect.bottom = outRect.top + h; |
| if ((gravity&(AXIS_CLIP<<AXIS_Y_SHIFT)) |
| == (AXIS_CLIP<<AXIS_Y_SHIFT)) { |
| if (outRect.top < container.top) { |
| outRect.top = container.top; |
| } |
| if (outRect.bottom > container.bottom) { |
| outRect.bottom = container.bottom; |
| } |
| } |
| break; |
| case AXIS_PULL_BEFORE<<AXIS_Y_SHIFT: |
| outRect.top = container.top + yAdj; |
| outRect.bottom = outRect.top + h; |
| if ((gravity&(AXIS_CLIP<<AXIS_Y_SHIFT)) |
| == (AXIS_CLIP<<AXIS_Y_SHIFT)) { |
| if (outRect.bottom > container.bottom) { |
| outRect.bottom = container.bottom; |
| } |
| } |
| break; |
| case AXIS_PULL_AFTER<<AXIS_Y_SHIFT: |
| outRect.bottom = container.bottom - yAdj; |
| outRect.top = outRect.bottom - h; |
| if ((gravity&(AXIS_CLIP<<AXIS_Y_SHIFT)) |
| == (AXIS_CLIP<<AXIS_Y_SHIFT)) { |
| if (outRect.top < container.top) { |
| outRect.top = container.top; |
| } |
| } |
| break; |
| default: |
| outRect.top = container.top + yAdj; |
| outRect.bottom = container.bottom + yAdj; |
| break; |
| } |
| } |
| |
| /** |
| * Apply a gravity constant to an object. |
| * |
| * @param gravity The desired placement of the object, as defined by the |
| * constants in this class. |
| * @param w The horizontal size of the object. |
| * @param h The vertical size of the object. |
| * @param container The frame of the containing space, in which the object |
| * will be placed. Should be large enough to contain the |
| * width and height of the object. |
| * @param xAdj Offset to apply to the X axis. If gravity is LEFT this |
| * pushes it to the right; if gravity is RIGHT it pushes it to |
| * the left; if gravity is CENTER_HORIZONTAL it pushes it to the |
| * right or left; otherwise it is ignored. |
| * @param yAdj Offset to apply to the Y axis. If gravity is TOP this pushes |
| * it down; if gravity is BOTTOM it pushes it up; if gravity is |
| * CENTER_VERTICAL it pushes it down or up; otherwise it is |
| * ignored. |
| * @param outRect Receives the computed frame of the object in its |
| * container. |
| * @param layoutDirection The layout direction. |
| * |
| * @see View#LAYOUT_DIRECTION_LTR |
| * @see View#LAYOUT_DIRECTION_RTL |
| */ |
| public static void apply(int gravity, int w, int h, Rect container, |
| int xAdj, int yAdj, Rect outRect, int layoutDirection) { |
| int absGravity = getAbsoluteGravity(gravity, layoutDirection); |
| apply(absGravity, w, h, container, xAdj, yAdj, outRect); |
| } |
| |
| /** |
| * Apply additional gravity behavior based on the overall "display" that an |
| * object exists in. This can be used after |
| * {@link #apply(int, int, int, Rect, int, int, Rect)} to place the object |
| * within a visible display. By default this moves or clips the object |
| * to be visible in the display; the gravity flags |
| * {@link #DISPLAY_CLIP_HORIZONTAL} and {@link #DISPLAY_CLIP_VERTICAL} |
| * can be used to change this behavior. |
| * |
| * @param gravity Gravity constants to modify the placement within the |
| * display. |
| * @param display The rectangle of the display in which the object is |
| * being placed. |
| * @param inoutObj Supplies the current object position; returns with it |
| * modified if needed to fit in the display. |
| */ |
| public static void applyDisplay(int gravity, Rect display, Rect inoutObj) { |
| if ((gravity&DISPLAY_CLIP_VERTICAL) != 0) { |
| if (inoutObj.top < display.top) inoutObj.top = display.top; |
| if (inoutObj.bottom > display.bottom) inoutObj.bottom = display.bottom; |
| } else { |
| int off = 0; |
| if (inoutObj.top < display.top) off = display.top-inoutObj.top; |
| else if (inoutObj.bottom > display.bottom) off = display.bottom-inoutObj.bottom; |
| if (off != 0) { |
| if (inoutObj.height() > (display.bottom-display.top)) { |
| inoutObj.top = display.top; |
| inoutObj.bottom = display.bottom; |
| } else { |
| inoutObj.top += off; |
| inoutObj.bottom += off; |
| } |
| } |
| } |
| |
| if ((gravity&DISPLAY_CLIP_HORIZONTAL) != 0) { |
| if (inoutObj.left < display.left) inoutObj.left = display.left; |
| if (inoutObj.right > display.right) inoutObj.right = display.right; |
| } else { |
| int off = 0; |
| if (inoutObj.left < display.left) off = display.left-inoutObj.left; |
| else if (inoutObj.right > display.right) off = display.right-inoutObj.right; |
| if (off != 0) { |
| if (inoutObj.width() > (display.right-display.left)) { |
| inoutObj.left = display.left; |
| inoutObj.right = display.right; |
| } else { |
| inoutObj.left += off; |
| inoutObj.right += off; |
| } |
| } |
| } |
| } |
| |
| /** |
| * Apply additional gravity behavior based on the overall "display" that an |
| * object exists in. This can be used after |
| * {@link #apply(int, int, int, Rect, int, int, Rect)} to place the object |
| * within a visible display. By default this moves or clips the object |
| * to be visible in the display; the gravity flags |
| * {@link #DISPLAY_CLIP_HORIZONTAL} and {@link #DISPLAY_CLIP_VERTICAL} |
| * can be used to change this behavior. |
| * |
| * @param gravity Gravity constants to modify the placement within the |
| * display. |
| * @param display The rectangle of the display in which the object is |
| * being placed. |
| * @param inoutObj Supplies the current object position; returns with it |
| * modified if needed to fit in the display. |
| * @param layoutDirection The layout direction. |
| * |
| * @see View#LAYOUT_DIRECTION_LTR |
| * @see View#LAYOUT_DIRECTION_RTL |
| */ |
| public static void applyDisplay(int gravity, Rect display, Rect inoutObj, int layoutDirection) { |
| int absGravity = getAbsoluteGravity(gravity, layoutDirection); |
| applyDisplay(absGravity, display, inoutObj); |
| } |
| |
| /** |
| * <p>Indicate whether the supplied gravity has a vertical pull.</p> |
| * |
| * @param gravity the gravity to check for vertical pull |
| * @return true if the supplied gravity has a vertical pull |
| */ |
| public static boolean isVertical(int gravity) { |
| return gravity > 0 && (gravity & VERTICAL_GRAVITY_MASK) != 0; |
| } |
| |
| /** |
| * <p>Indicate whether the supplied gravity has an horizontal pull.</p> |
| * |
| * @param gravity the gravity to check for horizontal pull |
| * @return true if the supplied gravity has an horizontal pull |
| */ |
| public static boolean isHorizontal(int gravity) { |
| return gravity > 0 && (gravity & RELATIVE_HORIZONTAL_GRAVITY_MASK) != 0; |
| } |
| |
| /** |
| * <p>Convert script specific gravity to absolute horizontal value.</p> |
| * |
| * if horizontal direction is LTR, then START will set LEFT and END will set RIGHT. |
| * if horizontal direction is RTL, then START will set RIGHT and END will set LEFT. |
| * |
| * |
| * @param gravity The gravity to convert to absolute (horizontal) values. |
| * @param layoutDirection The layout direction. |
| * @return gravity converted to absolute (horizontal) values. |
| */ |
| public static int getAbsoluteGravity(int gravity, int layoutDirection) { |
| int result = gravity; |
| // If layout is script specific and gravity is horizontal relative (START or END) |
| if ((result & RELATIVE_LAYOUT_DIRECTION) > 0) { |
| if ((result & Gravity.START) == Gravity.START) { |
| // Remove the START bit |
| result &= ~START; |
| if (layoutDirection == View.LAYOUT_DIRECTION_RTL) { |
| // Set the RIGHT bit |
| result |= RIGHT; |
| } else { |
| // Set the LEFT bit |
| result |= LEFT; |
| } |
| } else if ((result & Gravity.END) == Gravity.END) { |
| // Remove the END bit |
| result &= ~END; |
| if (layoutDirection == View.LAYOUT_DIRECTION_RTL) { |
| // Set the LEFT bit |
| result |= LEFT; |
| } else { |
| // Set the RIGHT bit |
| result |= RIGHT; |
| } |
| } |
| // Don't need the script specific bit any more, so remove it as we are converting to |
| // absolute values (LEFT or RIGHT) |
| result &= ~RELATIVE_LAYOUT_DIRECTION; |
| } |
| return result; |
| } |
| |
| /** |
| * @hide |
| */ |
| public static String toString(int gravity) { |
| final StringBuilder result = new StringBuilder(); |
| if ((gravity & FILL) == FILL) { |
| result.append("FILL").append(' '); |
| } else { |
| if ((gravity & FILL_VERTICAL) == FILL_VERTICAL) { |
| result.append("FILL_VERTICAL").append(' '); |
| } else { |
| if ((gravity & TOP) == TOP) { |
| result.append("TOP").append(' '); |
| } |
| if ((gravity & BOTTOM) == BOTTOM) { |
| result.append("BOTTOM").append(' '); |
| } |
| } |
| if ((gravity & FILL_HORIZONTAL) == FILL_HORIZONTAL) { |
| result.append("FILL_HORIZONTAL").append(' '); |
| } else { |
| if ((gravity & START) == START) { |
| result.append("START").append(' '); |
| } else if ((gravity & LEFT) == LEFT) { |
| result.append("LEFT").append(' '); |
| } |
| if ((gravity & END) == END) { |
| result.append("END").append(' '); |
| } else if ((gravity & RIGHT) == RIGHT) { |
| result.append("RIGHT").append(' '); |
| } |
| } |
| } |
| if ((gravity & CENTER) == CENTER) { |
| result.append("CENTER").append(' '); |
| } else { |
| if ((gravity & CENTER_VERTICAL) == CENTER_VERTICAL) { |
| result.append("CENTER_VERTICAL").append(' '); |
| } |
| if ((gravity & CENTER_HORIZONTAL) == CENTER_HORIZONTAL) { |
| result.append("CENTER_HORIZONTAL").append(' '); |
| } |
| } |
| if (result.length() == 0) { |
| result.append("NO GRAVITY").append(' '); |
| } |
| if ((gravity & DISPLAY_CLIP_VERTICAL) == DISPLAY_CLIP_VERTICAL) { |
| result.append("DISPLAY_CLIP_VERTICAL").append(' '); |
| } |
| if ((gravity & DISPLAY_CLIP_HORIZONTAL) == DISPLAY_CLIP_HORIZONTAL) { |
| result.append("DISPLAY_CLIP_HORIZONTAL").append(' '); |
| } |
| result.deleteCharAt(result.length() - 1); |
| return result.toString(); |
| } |
| } |
