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Commit 6e530ea8 authored by Adam Barth's avatar Adam Barth
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Make pesto demo scroll fast (#4443) 

We can viewport the content using a ScrollableGrid. Also, we can use the
padding mechanisms of the grid to avoid extra padding widgets.
parent 440aa5ee
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Showing with 107 additions and 85 deletions
examples/flutter_gallery/lib/demo/pesto_demo.dart
View file @ 6e530ea8
......@@ -69,22 +69,19 @@ class _PestoDemoState extends State<PestoDemo> {
child: new Icon(icon: Icons.edit),
onPressed: () { }
),
body: new Block(
padding: new EdgeInsets.only(top: _kAppBarHeight + statusBarHeight),
children: <Widget>[
new Padding(
padding: const EdgeInsets.all(8.0),
child: new MaxTileWidthGrid(
maxTileWidth: 500.0,
children: recipes.map(
(Recipe recipe) => new _RecipeCard(
recipe: recipe,
onTap: () { _showRecipe(context, recipe); }
)
).toList()
)
body: new ScrollableGrid(
delegate: new MaxTileWidthGridDelegate(
maxTileWidth: 500.0,
rowSpacing: 8.0,
columnSpacing: 8.0,
padding: new EdgeInsets.fromLTRB(8.0, 8.0 + _kAppBarHeight + statusBarHeight, 8.0, 8.0)
),
children: recipes.map(
(Recipe recipe) => new _RecipeCard(
recipe: recipe,
onTap: () { _showRecipe(context, recipe); }
)
]
)
)
)
);
......@@ -200,42 +197,39 @@ class _RecipeCard extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new Padding(
padding: const EdgeInsets.all(4.0),
child: new GestureDetector(
onTap: onTap,
child: new Card(
child: new Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
new AssetImage(
name: recipe.imagePath,
fit: ImageFit.scaleDown
),
new Flexible(
child: new Row(
children: <Widget>[
new Padding(
padding: const EdgeInsets.all(16.0),
child: new AssetImage(
width: 48.0,
height: 48.0,
name: recipe.ingredientsImagePath
)
),
new Column(
crossAxisAlignment: CrossAxisAlignment.start,
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Text(recipe.name, style: titleStyle),
new Text(recipe.author, style: authorStyle),
]
return new GestureDetector(
onTap: onTap,
child: new Card(
child: new Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
new AssetImage(
name: recipe.imagePath,
fit: ImageFit.scaleDown
),
new Flexible(
child: new Row(
children: <Widget>[
new Padding(
padding: const EdgeInsets.all(16.0),
child: new AssetImage(
width: 48.0,
height: 48.0,
name: recipe.ingredientsImagePath
)
]
)
),
new Column(
crossAxisAlignment: CrossAxisAlignment.start,
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Text(recipe.name, style: titleStyle),
new Text(recipe.author, style: authorStyle),
]
)
]
)
]
)
)
]
)
)
);
......
packages/flutter/lib/src/rendering/grid.dart
View file @ 6e530ea8
......@@ -27,11 +27,11 @@ bool _debugIsMonotonic(List<double> offsets) {
return result;
}
List<double> _generateRegularOffsets(int count, double size) {
List<double> _generateRegularOffsets(int count, double extent) {
final int length = count + 1;
final List<double> result = new Float64List(length);
for (int i = 0; i < length; ++i)
result[i] = i * size;
result[i] = i * extent;
return result;
}
......@@ -62,20 +62,26 @@ class GridSpecification {
}
/// Creates a grid specification containing a certain number of equally sized tiles.
/// The tileWidth is the sum of the width of the child it will contain and
/// columnSpacing (even if columnCount is 1). Similarly tileHeight is child's height
/// plus rowSpacing. If the tiles are to completely fill the grid, then their size
/// should be based on the grid's padded interior.
///
/// The `tileWidth` and `tileHeight` is the horizontal and vertical
/// (respectively) extent that each child will be allocated in the grid. The
/// tiles will have [columnSpacing] space between them horizontally and
/// [rowSpacing] space between them vertically.
///
/// If the tiles are to completely fill the grid, then their size should be
/// based on the grid's padded interior and the column and row spacing.
GridSpecification.fromRegularTiles({
double tileWidth,
double tileHeight,
int columnCount,
int rowCount,
this.rowSpacing: 0.0,
this.columnSpacing: 0.0,
double columnSpacing: 0.0,
double rowSpacing: 0.0,
this.padding: EdgeInsets.zero
}) : columnOffsets = _generateRegularOffsets(columnCount, tileWidth),
rowOffsets = _generateRegularOffsets(rowCount, tileHeight) {
}) : columnOffsets = _generateRegularOffsets(columnCount, tileWidth + columnSpacing),
rowOffsets = _generateRegularOffsets(rowCount, tileHeight + rowSpacing),
columnSpacing = columnSpacing,
rowSpacing = rowSpacing {
assert(_debugIsMonotonic(columnOffsets));
assert(_debugIsMonotonic(rowOffsets));
assert(columnSpacing != null && columnSpacing >= 0.0);
......@@ -85,10 +91,14 @@ class GridSpecification {
/// The offsets of the column boundaries in the grid.
///
/// The first offset is the offset of the left edge of the left-most column
/// The first offset is the offset of the left edge of the left-most tile
/// from the left edge of the interior of the grid's padding (0.0 if the padding
/// is EdgeOffsets.zero). The last offset is the offset of the right edge of
/// the right-most column from the left edge of the interior of the grid's padding.
/// is EdgeOffsets.zero). The difference between successive entries is the
/// tile width plus the column spacing.
///
/// The last offset is the offset of the right edge of the right-most tile
/// from the left edge of the interior of the grid's padding (less the
/// [columnSpacing]).
///
/// If there are n columns in the grid, there should be n + 1 entries in this
/// list. The right edge of the last column is defined as columnOffsets(n), i.e.
......@@ -97,22 +107,26 @@ class GridSpecification {
/// The offsets of the row boundaries in the grid.
///
/// The first offset is the offset of the top edge of the top-most row from
/// The first offset is the offset of the top edge of the top-most tile from
/// the top edge of the interior of the grid's padding (usually if the padding
/// is EdgeOffsets.zero). The last offset is the offset of the bottom edge of
/// the bottom-most column from the top edge of the interior of the grid's padding.
/// is EdgeOffsets.zero). The difference between successive entries is the
/// tile height plus the row spacing
///
/// The last offset is the offset of the bottom edge of the bottom-most tile
/// from the top edge of the interior of the grid's padding. (less the
/// [rowSpacing])
///
/// If there are n rows in the grid, there should be n + 1 entries in this
/// list. The bottom edge of the last row is defined as rowOffsets(n), i.e.
/// the top edge of an extra row.
final List<double> rowOffsets;
/// The vertical distance between rows.
final double rowSpacing;
/// The horizontal distance between columns.
/// The horizontal padding between columns.
final double columnSpacing;
/// The vertical padding between rows.
final double rowSpacing;
/// The interior padding of the grid.
///
/// The grid's size encloses the spaced rows and columns and is then inflated
......@@ -120,7 +134,12 @@ class GridSpecification {
final EdgeInsets padding;
/// The size of the grid.
Size get gridSize => new Size(columnOffsets.last + padding.horizontal, rowOffsets.last + padding.vertical);
Size get gridSize {
return new Size(
columnOffsets.last + padding.horizontal - columnSpacing,
rowOffsets.last + padding.vertical - rowSpacing
);
}
/// The number of columns in this grid.
int get columnCount => columnOffsets.length - 1;
......@@ -271,10 +290,10 @@ abstract class GridDelegateWithInOrderChildPlacement extends GridDelegate {
assert(padding != null && padding.isNonNegative);
}
/// The horizontal distance between columns.
/// The horizontal padding between columns.
final double columnSpacing;
/// The vertical distance between rows.
/// The vertical padding between rows.
final double rowSpacing;
/// Insets for the entire grid.
......@@ -327,9 +346,11 @@ class FixedColumnCountGridDelegate extends GridDelegateWithInOrderChildPlacement
@override
GridSpecification getGridSpecification(BoxConstraints constraints, int childCount) {
assert(constraints.maxWidth < double.INFINITY);
int rowCount = (childCount / columnCount).ceil();
double tileWidth = math.max(0.0, constraints.maxWidth - padding.horizontal + columnSpacing) / columnCount;
double tileHeight = tileWidth / tileAspectRatio;
final int rowCount = (childCount / columnCount).ceil();
final double interiorWidth = constraints.maxWidth - padding.horizontal;
final double columnWidth = interiorWidth / columnCount;
final double tileWidth = math.max(0.0, columnWidth - columnSpacing);
final double tileHeight = tileWidth / tileAspectRatio;
return new GridSpecification.fromRegularTiles(
tileWidth: tileWidth,
tileHeight: tileHeight,
......@@ -416,10 +437,17 @@ class MaxTileWidthGridDelegate extends GridDelegateWithInOrderChildPlacement {
);
}
final double gridWidth = math.max(0.0, constraints.maxWidth - padding.horizontal);
int columnCount = (gridWidth / maxTileWidth).ceil();
int rowCount = (childCount / columnCount).ceil();
double tileWidth = gridWidth / columnCount;
double tileHeight = tileWidth / tileAspectRatio;
// We inflate the gridWidth by columnSpacing because the columnSpacing for
// the rightmost tile in the grid doesn't actually consume space in the
// grid because the rightmost tile is flush to the right interior edge of
// the grid.
final double totalColumnExtent = gridWidth + columnSpacing;
final double maxColumnWidth = maxTileWidth + columnSpacing;
final int columnCount = (totalColumnExtent / maxColumnWidth).ceil();
final int rowCount = (childCount / columnCount).ceil();
final double columnWidth = totalColumnExtent / columnCount;
final double tileWidth = columnWidth - columnSpacing;
final double tileHeight = tileWidth / tileAspectRatio;
return new GridSpecification.fromRegularTiles(
tileWidth: tileWidth,
tileHeight: tileHeight,
......@@ -618,13 +646,13 @@ class RenderGrid extends RenderVirtualViewport<GridParentData> {
assert(placement.column + placement.columnSpan < _specification.columnOffsets.length);
assert(placement.row + placement.rowSpan < _specification.rowOffsets.length);
double tileLeft = gridLeftPadding + _specification.columnOffsets[placement.column];
double tileRight = gridLeftPadding + _specification.columnOffsets[placement.column + placement.columnSpan];
double tileTop = gridTopPadding + _specification.rowOffsets[placement.row];
double tileBottom = gridTopPadding + _specification.rowOffsets[placement.row + placement.rowSpan];
final double tileLeft = gridLeftPadding + _specification.columnOffsets[placement.column];
final double tileRight = gridLeftPadding + _specification.columnOffsets[placement.column + placement.columnSpan] - _specification.columnSpacing;
final double tileTop = gridTopPadding + _specification.rowOffsets[placement.row];
final double tileBottom = gridTopPadding + _specification.rowOffsets[placement.row + placement.rowSpan] - _specification.rowSpacing;
double childWidth = math.max(0.0, tileRight - tileLeft - _specification.columnSpacing);
double childHeight = math.max(0.0, tileBottom - tileTop - _specification.rowSpacing);
final double childWidth = math.max(0.0, tileRight - tileLeft);
final double childHeight = math.max(0.0, tileBottom - tileTop);
child.layout(new BoxConstraints(
minWidth: childWidth,
......
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