@nativescript/core
Version:
A JavaScript library providing an easy to use api for interacting with iOS and Android platform APIs.
161 lines • 7.66 kB
JavaScript
// Requires
import { layout } from '../../../../utils';
import { Trace } from '../../../../trace';
export class ViewHelper {
static measureChild(parent, child, widthMeasureSpec, heightMeasureSpec) {
let measureWidth = 0;
let measureHeight = 0;
if (child && !child.isCollapsed) {
const widthSpec = parent ? parent._currentWidthMeasureSpec : widthMeasureSpec;
const heightSpec = parent ? parent._currentHeightMeasureSpec : heightMeasureSpec;
const width = layout.getMeasureSpecSize(widthSpec);
const widthMode = layout.getMeasureSpecMode(widthSpec);
const height = layout.getMeasureSpecSize(heightSpec);
const heightMode = layout.getMeasureSpecMode(heightSpec);
child._updateEffectiveLayoutValues(width, widthMode, height, heightMode);
const style = child.style;
const horizontalMargins = child.effectiveMarginLeft + child.effectiveMarginRight;
const verticalMargins = child.effectiveMarginTop + child.effectiveMarginBottom;
const childWidthMeasureSpec = ViewHelper.getMeasureSpec(widthMeasureSpec, horizontalMargins, child.effectiveWidth, style.horizontalAlignment === 'stretch');
const childHeightMeasureSpec = ViewHelper.getMeasureSpec(heightMeasureSpec, verticalMargins, child.effectiveHeight, style.verticalAlignment === 'stretch');
if (Trace.isEnabled()) {
Trace.write(`${child.parent} :measureChild: ${child} ${layout.measureSpecToString(childWidthMeasureSpec)}, ${layout.measureSpecToString(childHeightMeasureSpec)}}`, Trace.categories.Layout);
}
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
measureWidth = Math.round(child.getMeasuredWidth() + horizontalMargins);
measureHeight = Math.round(child.getMeasuredHeight() + verticalMargins);
}
return { measuredWidth: measureWidth, measuredHeight: measureHeight };
}
static layoutChild(parent, child, left, top, right, bottom, setFrame = true) {
if (!child || child.isCollapsed) {
return;
}
const childStyle = child.style;
let childTop;
let childLeft;
let childWidth = child.getMeasuredWidth();
let childHeight = child.getMeasuredHeight();
const effectiveMarginTop = child.effectiveMarginTop;
const effectiveMarginBottom = child.effectiveMarginBottom;
let vAlignment;
if (child.effectiveHeight >= 0 && childStyle.verticalAlignment === 'stretch') {
vAlignment = 'middle';
}
else {
vAlignment = childStyle.verticalAlignment;
}
switch (vAlignment) {
case 'top':
childTop = top + effectiveMarginTop;
break;
case 'middle':
childTop = top + (bottom - top - childHeight + (effectiveMarginTop - effectiveMarginBottom)) / 2;
break;
case 'bottom':
childTop = bottom - childHeight - effectiveMarginBottom;
break;
case 'stretch':
default:
childTop = top + effectiveMarginTop;
childHeight = bottom - top - (effectiveMarginTop + effectiveMarginBottom);
if (childHeight < 0) {
childHeight = 0;
}
break;
}
const effectiveMarginLeft = child.effectiveMarginLeft;
const effectiveMarginRight = child.effectiveMarginRight;
let hAlignment;
if (child.effectiveWidth >= 0 && childStyle.horizontalAlignment === 'stretch') {
hAlignment = 'center';
}
else {
hAlignment = childStyle.horizontalAlignment;
}
switch (hAlignment) {
case 'left':
childLeft = left + effectiveMarginLeft;
break;
case 'center':
childLeft = left + (right - left - childWidth + (effectiveMarginLeft - effectiveMarginRight)) / 2;
break;
case 'right':
childLeft = right - childWidth - effectiveMarginRight;
break;
case 'stretch':
default:
childLeft = left + effectiveMarginLeft;
childWidth = right - left - (effectiveMarginLeft + effectiveMarginRight);
if (childWidth < 0) {
childWidth = 0;
}
break;
}
const childRight = Math.round(childLeft + childWidth);
const childBottom = Math.round(childTop + childHeight);
childLeft = Math.round(childLeft);
childTop = Math.round(childTop);
if (Trace.isEnabled()) {
Trace.write(child.parent + ' :layoutChild: ' + child + ' ' + childLeft + ', ' + childTop + ', ' + childRight + ', ' + childBottom, Trace.categories.Layout);
}
child.layout(childLeft, childTop, childRight, childBottom, setFrame);
}
static resolveSizeAndState(size, specSize, specMode, childMeasuredState) {
let result = size;
switch (specMode) {
case layout.UNSPECIFIED:
result = Math.ceil(size);
break;
case layout.AT_MOST:
if (specSize < size) {
result = Math.ceil(specSize) | layout.MEASURED_STATE_TOO_SMALL;
}
break;
case layout.EXACTLY:
result = Math.ceil(specSize);
break;
}
return result | (childMeasuredState & layout.MEASURED_STATE_MASK);
}
static combineMeasuredStates(curState, newState) {
return curState | newState;
}
static getMeasureSpec(parentSpec, margins, childLength, stretched) {
const parentLength = layout.getMeasureSpecSize(parentSpec);
const parentSpecMode = layout.getMeasureSpecMode(parentSpec);
let resultSize;
let resultMode;
// We want a specific size... let be it.
if (childLength >= 0) {
// If mode !== UNSPECIFIED we take the smaller of parentLength and childLength
// Otherwise we will need to clip the view but this is not possible in all Android API levels.
// TODO: remove Math.min(parentLength, childLength)
resultSize = parentSpecMode === layout.UNSPECIFIED ? childLength : Math.min(parentLength, childLength);
resultMode = layout.EXACTLY;
}
else {
switch (parentSpecMode) {
// Parent has imposed an exact size on us
case layout.EXACTLY:
resultSize = Math.max(0, parentLength - margins);
// if stretched - nativeView wants to be our size. So be it.
// else - nativeView wants to determine its own size. It can't be bigger than us.
resultMode = stretched ? layout.EXACTLY : layout.AT_MOST;
break;
// Parent has imposed a maximum size on us
case layout.AT_MOST:
resultSize = Math.max(0, parentLength - margins);
resultMode = layout.AT_MOST;
break;
// Equivalent to measure with Infinity.
case layout.UNSPECIFIED:
resultSize = 0;
resultMode = layout.UNSPECIFIED;
break;
}
}
return layout.makeMeasureSpec(resultSize, resultMode);
}
}
//# sourceMappingURL=view-helper-common.js.map