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* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores
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package com.codename1.ui.layouts;
import com.codename1.ui.Component;
import com.codename1.ui.Container;
import com.codename1.ui.geom.Dimension;
import com.codename1.ui.plaf.Style;
import com.codename1.ui.plaf.UIManager;
/**
* <p>FlowLayout is the default layout manager for Codename One Containers and Forms. It places components
* in a row one after another based on their preferred size. When it reaches the edge of the container it will break
* a line and start a new row. </p>
* <script src="https://gist.github.com/codenameone/124cab8d0c1da82756f1.js"></script>
* <img src="https://www.codenameone.com/img/developer-guide/flow-layout.png" alt="Result of FlowLayout code" />
*
* <p>
* Since flow layout isn't a constraint based layout it has a bunch of very useful enclose methods that can significantly
* reduce the code required to create the same UI e.g.:
* </p>
* <script src="https://gist.github.com/codenameone/3481c77f93726745ad28.js"></script>
*
* <p>
* This class works nicely for simple elements, however since Codename One doesn't reflow recursively (for performance)
* it can't accurately handle complex layouts. As a result when an element of varying size is placed in a flow layout
* this confuses the line breaking logic and fails in odd ways. That is why this layout should only be used for relatively
* simple use cases.
* </p>
*
* <p>
* Flow layout supports aligning the component horizontally and vertically, it defaults to the top left alignment for
* LTR languages. E.g. the following alignments are supported thru the usage of <code>setAlign</code> &
* <code>setValign</code>.
* </p>
* <p>E.g. you can align to the center</p>
* <img src="https://www.codenameone.com/img/developer-guide/flow-layout-center.png" alt="Flow layout align center" />
*
* <p>You can align to the right</p>
* <img src="https://www.codenameone.com/img/developer-guide/flow-layout-right.png" alt="Flow layout align right" />
*
* <p>You can align to the center and the middle horizontally</p>
* <img src="https://www.codenameone.com/img/developer-guide/flow-layout-center-middle.png" alt="Flow layout align middle" />
*
* <p>There are quite a few additional combinations that are possible with these API's.</p>
*
* @see BoxLayout see the box layout X which is often a better choice than flow layout.
* @author Nir Shabi
*/
public class FlowLayout extends Layout{
private boolean fillRows;
private int orientation = Component.LEFT;
private int valign = Component.TOP;
private boolean vAlignByRow;
/**
* Creates a new instance of FlowLayout with left alignment
*/
public FlowLayout() {
}
/**
* Creates a new instance of FlowLayout with the given orientation one of
* LEFT, RIGHT or CENTER
*
* @param orientation the orientation value
*/
public FlowLayout(int orientation) {
this.orientation = orientation;
}
/**
* Creates a new instance of FlowLayout with the given orientation one of
* LEFT, RIGHT or CENTER and the vertical orientation
*
* @param orientation the orientation value
* @param valign the vertical orientation one of Component.TOP/BOTTOM/CENTER
*/
public FlowLayout(int orientation, int valign) {
this.orientation = orientation;
this.valign = valign;
}
/**
* {@inheritDoc}
*/
public void layoutContainer(Container parent) {
Style s = parent.getStyle();
int x = s.getPaddingLeft(parent.isRTL());
int width = parent.getLayoutWidth() - parent.getSideGap() - s.getPaddingLeft(parent.isRTL()) - x;
boolean rtl = parent.isRTL();
if(rtl) {
x += parent.getSideGap();
}
int initX = x;
int y = s.getPaddingTop();
int rowH=0;
int start=0;
int rowBaseline=0;
int maxComponentWidth = width;
int numOfcomponents = parent.getComponentCount();
for(int i=0; i< numOfcomponents; i++){
Component cmp = parent.getComponentAt(i);
Style style = cmp.getStyle();
int marginX = style.getMarginLeftNoRTL() + style.getMarginRightNoRTL();
cmp.setWidth(Math.min(maxComponentWidth - marginX, cmp.getPreferredW()));
cmp.setHeight(cmp.getPreferredH());
if((x == s.getPaddingLeft(rtl)) || ( x+ cmp.getPreferredW() <= width) ) {
// We take the actual LEFT since drawing is done in reverse
x += cmp.getStyle().getMarginLeftNoRTL();
if(rtl) {
cmp.setX(Math.max(width + initX - (x - initX) - cmp.getPreferredW(), style.getMarginLeftNoRTL()));
} else {
cmp.setX(x);
}
cmp.setY(y + cmp.getStyle().getMarginTop());
x += cmp.getWidth() + cmp.getStyle().getMarginRightNoRTL();
rowH = Math.max(rowH, cmp.getHeight() + cmp.getStyle().getMarginTop()+ cmp.getStyle().getMarginBottom());
if ( valign == Component.BASELINE ){
int cmpPrefH = cmp.getPreferredH();
int cmpBaseline = cmp.getBaseline(cmp.getPreferredW(), cmpPrefH);
rowBaseline = Math.max(rowBaseline, cmpBaseline + cmp.getStyle().getMarginTop());
rowH = Math.max(rowH, rowBaseline + cmp.getStyle().getMarginBottom() + cmpPrefH-cmpBaseline);
}
} else {
moveComponents(parent, s.getPaddingLeft(rtl), y, width - s.getPaddingLeft(rtl) - x, rowH, start, i, rowBaseline);
if(fillRows) {
fillRow(parent, width, start, i);
}
x = initX+cmp.getStyle().getMarginLeftNoRTL();
y += rowH;
rowBaseline = 0;
if(rtl) {
cmp.setX(Math.max(width + initX - (x - initX) - cmp.getPreferredW(), style.getMarginLeftNoRTL()));
} else {
cmp.setX(x);
}
cmp.setY(y + cmp.getStyle().getMarginTop());
rowH = cmp.getPreferredH()+ cmp.getStyle().getMarginTop()+ cmp.getStyle().getMarginBottom();
if ( valign == Component.BASELINE ){
int cmpPrefH = cmp.getPreferredH();
int cmpBaseline = cmp.getBaseline(cmp.getPreferredW(), cmpPrefH);
rowBaseline = Math.max(rowBaseline, cmpBaseline + cmp.getStyle().getMarginTop());
rowH = Math.max(rowH, rowBaseline + cmp.getStyle().getMarginBottom() + cmpPrefH-cmpBaseline);
}
x += cmp.getPreferredW()+ cmp.getStyle().getMarginRightNoRTL();
start = i;
}
}
moveComponents(parent, s.getPaddingLeft(rtl), y, width - s.getPaddingLeft(rtl) - x, rowH, start, numOfcomponents, rowBaseline);
if(fillRows) {
fillRow(parent, width, start, numOfcomponents);
}
}
/**
* This method tries to fill up the available space in a row.
* This method is called if isFillRows() returns true.
*
* @param target the parent container
* @param width the width of the row to fill
* @param start the index of the first component in this row
* @param end the index of the last component in this row
*/
protected void fillRow(Container target, int width, int start, int end) {
int available = width;
for(int iter = start ; iter < end ; iter++) {
Component c = target.getComponentAt(iter);
available -= (c.getWidth() + c.getStyle().getMarginRightNoRTL() +
c.getStyle().getMarginLeftNoRTL());
}
if(available > 0 && end - start > 0) {
int perComponent = available / (end - start);
int lastComponent = perComponent + available % (end - start);
if(perComponent > 0) {
int addOffset = 0;
boolean rtl = target.isRTL();
for(int iter = start ; iter < end - 1 ; iter++) {
Component c = target.getComponentAt(iter);
c.setWidth(c.getWidth() + perComponent);
if(rtl) {
addOffset += perComponent;
c.setX(c.getX() - addOffset);
} else {
c.setX(c.getX() + addOffset);
addOffset += perComponent;
}
}
Component c = target.getComponentAt(end - 1);
if(rtl) {
addOffset += lastComponent;
c.setX(c.getX() - addOffset);
} else {
c.setX(c.getX() + addOffset);
}
c.setWidth(c.getWidth() + lastComponent);
} else {
Component c = target.getComponentAt(end - 1);
c.setWidth(c.getWidth() + lastComponent);
}
}
}
private void moveComponents(Container target, int x, int y, int width, int height, int rowStart, int rowEnd, int baseline ) {
switch (orientation) {
case Component.CENTER:
// this will remove half of last gap
if (target.isRTL()) {
x -= (width) / 2;
} else {
x += (width) / 2;
}
break;
case Component.RIGHT:
x+=width; // this will remove the last gap
break;
}
Style parentStyle = target.getStyle();
int parentPadding = parentStyle.getHorizontalPadding();
for (int i = rowStart ; i < rowEnd ; i++) {
Component m = target.getComponentAt(i);
Style style = m.getStyle();
int marginX = style.getMarginLeftNoRTL() + style.getMarginRightNoRTL();
if(m.getWidth() + marginX < target.getWidth() - parentPadding){
m.setX(m.getX()+ x);
}
int marginTop = style.getMarginTop();
switch(valign) {
case Component.BOTTOM:
if (vAlignByRow) {
m.setY(y + Math.max(marginTop, height - m.getHeight()) - style.getMarginBottom());
} else {
m.setY(y + Math.max(marginTop, target.getHeight() - m.getHeight()) - style.getMarginBottom());
}
break;
case Component.CENTER:
if (vAlignByRow) {
m.setY(y + Math.max(marginTop, (height - m.getHeight()) / 2));
} else {
m.setY(y + Math.max(marginTop, (target.getHeight() - m.getHeight()) / 2));
}
break;
case Component.BASELINE:
m.setY(y + Math.max(marginTop, baseline - m.getBaseline(m.getWidth(), m.getHeight())));
break;
default:
m.setY(y + marginTop);
break;
}
}
}
private Dimension dim = new Dimension(0, 0);
/**
* {@inheritDoc}
*/
public Dimension getPreferredSize(Container parent) {
int parentWidth = parent.getWidth();
if(parentWidth == 0){
parent.invalidate();
}
int width = 0;
int height = 0;
int w = 0;
int numOfcomponents = parent.getComponentCount();
Style parentStyle = parent.getStyle();
int parentPadding = parentStyle.getHorizontalPadding();
for(int i=0; i< numOfcomponents; i++){
Component cmp = parent.getComponentAt(i);
height = Math.max(height, cmp.getPreferredH() + cmp.getStyle().getMarginTop()+ cmp.getStyle().getMarginBottom());
int prefW = cmp.getPreferredW()+ cmp.getStyle().getMarginRightNoRTL()+ cmp.getStyle().getMarginLeftNoRTL();
w += prefW;
//we need to break a line
if (parentWidth > parentPadding && w > parentWidth && i > 0) {
height += cmp.getPreferredH() + cmp.getStyle().getMarginTop() + cmp.getStyle().getMarginBottom();
width = Math.max(w, width);
w = prefW;
}
}
width = Math.max(w, width);
dim.setWidth(width + parent.getStyle().getPaddingLeftNoRTL()+ parent.getStyle().getPaddingRightNoRTL());
dim.setHeight(height + parent.getStyle().getPaddingTop()+ parent.getStyle().getPaddingBottom());
return dim;
}
/**
* {@inheritDoc}
*/
public String toString() {
return "FlowLayout";
}
/**
* Indicates whether the layout manager should try to fill up the available space
* in the row
*
* @return the fillRows
*/
public boolean isFillRows() {
return fillRows;
}
/**
* Indicates whether the layout manager should try to fill up the available space
* in the row
*
* @param fillRows the fillRows to set
*/
public void setFillRows(boolean fillRows) {
this.fillRows = fillRows;
}
/**
* Indicates vertical alignment within the flow layout
*
* @return Component.TOP/BOTTOM/CENTER
*/
public int getValign() {
return valign;
}
/**
* Indicates vertical alignment within the flow layout
*
* @param valign one of Component.TOP/BOTTOM/CENTER
*/
public void setValign(int valign) {
this.valign = valign;
}
/**
* When set to true vertical alignment will be performed by row (components within the container will be aligned vertically to each other in the same row)
* When set to false (which is default) vertical alignment relates to the alignment of this container in regards to external components
*
* @param internal true for internal, false otherwise
*/
public void setValignByRow(boolean internal) {
vAlignByRow=internal;
}
/**
* Returns whether vertical alignment is done internally or externally
*
* @return whether vertical alignment is done internally or externally
*/
public boolean isValignByRow() {
return vAlignByRow;
}
/**
* Alignment of the flow layout, defaults to LEFT
*
* @return the orientation
*/
public int getAlign() {
return orientation;
}
/**
* Alignment of the flow layout, defaults to LEFT
*
* @param orientation the orientation to set
*/
public void setAlign(int orientation) {
this.orientation = orientation;
}
/**
* {@inheritDoc}
*/
public boolean equals(Object o) {
return super.equals(o) && ((FlowLayout)o).orientation == orientation &&
((FlowLayout)o).valign == valign &&
((FlowLayout)o).fillRows == fillRows;
}
/**
* <p>Shorthand for {@link com.codename1.ui.Container#encloseIn(com.codename1.ui.layouts.Layout, com.codename1.ui.Component...)}
* with a {@code FlowLayout instance} see:</p>
* <script src="https://gist.github.com/codenameone/3481c77f93726745ad28.js"></script>
*
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseIn(Component... cmps) {
return Container.encloseIn(new FlowLayout(), cmps);
}
/**
* Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER), cmps);
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseCenter(Component... cmps) {
return Container.encloseIn(new FlowLayout(Component.CENTER), cmps);
}
/**
* Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT), cmps);
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseRight(Component... cmps) {
return Container.encloseIn(new FlowLayout(Component.RIGHT), cmps);
}
/**
* Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER), cmps);
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseMiddle(Component... cmps) {
return Container.encloseIn(new FlowLayout(Component.LEFT, Component.CENTER), cmps);
}
/**
* Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.CENTER), cmps);
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseCenterMiddle(Component... cmps) {
return Container.encloseIn(new FlowLayout(Component.CENTER, Component.CENTER), cmps);
}
/**
* Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.CENTER), cmps);
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseRightMiddle(Component... cmps) {
return Container.encloseIn(new FlowLayout(Component.RIGHT, Component.CENTER), cmps);
}
/**
* Shorthand for Container.encloseIn(new FlowLayout(Component.LEFT, Component.BOTTOM), cmps);
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseBottom(Component... cmps) {
return Container.encloseIn(new FlowLayout(Component.LEFT, Component.BOTTOM), cmps);
}
/**
* Shorthand for Container.encloseIn(new FlowLayout(Component.CENTER, Component.BOTTOM), cmps);
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseCenterBottom(Component... cmps) {
return Container.encloseIn(new FlowLayout(Component.CENTER, Component.BOTTOM), cmps);
}
/**
* Shorthand for Container.encloseIn(new FlowLayout(Component.RIGHT, Component.BOTTOM), cmps);
* @param cmps the components to enclose in a new container
* @return the new container
*/
public static Container encloseRightBottom(Component... cmps) {
return Container.encloseIn(new FlowLayout(Component.RIGHT, Component.BOTTOM), cmps);
}
}