The Cost of a Brush

[Shaggy Hiker]

Painting in WPF is done with brushes. There appears to be two ways to do this, and I'm wondering what the cost is.

The way that is generally described is the naïve approach:

SomeControl.Background = New SolidColorBrush(Colors.Green)

This certainly looks like it is creating a new instance of a class. How long does that class live? What is the impact on memory?

Alternatively, since I might well be using a brush with a color of green in many different places if I am using it at all, then I could create one brush at form scope and use it in various places.

For the most part, this will be no big deal. The benefit of creating it in one place is pretty minimal if I will only be using that green brush in a few places. However, there is a time when I am creating a new brush every 100 ms, and the brushes might not be repeated...well, maybe not EVER, as it might cycle through every possible color at a rate of 10 colors per second.

In Windows.Forms, this wasn't a big deal, because all I was creating was a color structure, which had no memory implications. Creating a class just might.

So, the naïve approach for this would be to create a new brush for each new color. The better approach would be to use one brush at form scope and change the color property. This is the approach I took, I just don't know whether I was being reasonably cautious, or overly cautious.

Also, it seems like I could use one brush for all painting and change the color as needed. Is there a best practice here?

[PlausiblyDamp]

On my phone at the moment and can't look this up but I seem to remember reading somewhere that SolidColorBrush has an optimised implementation for known colours. So I suspect something like your code wouldn't create a new brush each time, but using a custom RGB colour probably would.

[Shaggy Hiker]

I forgot that I started this thread. Still not certain, I suppose. The approach I took was perhaps overly cautious, but I might revisit this later on.

[PlausiblyDamp]

I forgot that I started this thread. Still not certain, I suppose. The approach I took was perhaps overly cautious, but I might revisit this later on.

Completely forgot about this thread as well...

https://source.dot.net/#Presentation...db4a721050df52 is the source, around line 264 you can see the cache used for known colours.

[szlamany]

It has been so long since I've been in WPF - but is this not the whole reason for XAML files? So these resources get pre-built?

<Window x:Class="xxx.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:lvsort="clr-namespace:WpfListViewSorting"
    Title="xxxxxxxxx Management Software v1.113                    ** CONFIDENTIAL: NOT FOR DISTRIBUTION **" Height="575" Width="875" Icon="xxxxxx.ico" Loaded="Window_Loaded">
    <Window.Resources>
        <LinearGradientBrush x:Key="ButtonBrush" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="#FFFFFF" Offset="0"/>
            <GradientStop Color="#FFFFFF" Offset="0.5"/>
            <GradientStop Color="#FFFFFF" Offset="0.5"/>
            <GradientStop Color="#FFFFFF" Offset="1"/>
        </LinearGradientBrush>

        <LinearGradientBrush x:Key="ButtonBrushx" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="#FFF3F3F3" Offset="0"/>
            <GradientStop Color="#FFEBEBEB" Offset="0.5"/>
            <GradientStop Color="#FFDDDDDD" Offset="0.5"/>
            <GradientStop Color="#FFFCF9FC" Offset="1"/>
        </LinearGradientBrush>
        <Style x:Key="ButtonStylex">
            <Setter Property="Control.Margin" Value="2"></Setter>
            <Setter Property="Control.BorderBrush" Value="{x:Null}"></Setter>
            <EventSetter Event="Button.Click" Handler="Button_Click" />
        </Style>
        <Style x:Key="ButtonStyle">
            <Setter Property="Control.Template">
                <Setter.Value>
                    <ControlTemplate TargetType="Button">
                        <Border Name="shortcutbutton"  
                    BorderThickness="0 0 0 0"
                    BorderBrush="#D0D1D7"
                    Background="#FFFFFF">
                            <ContentPresenter Margin="2" 
                                  HorizontalAlignment="Center"
                                  VerticalAlignment="Center" 
                                  RecognizesAccessKey="True"/>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsMouseOver" Value="true">
                                <Setter TargetName="shortcutbutton" Property="Background" Value="#FFFFFF" />
                                <Setter TargetName="shortcutbutton" Property="BorderBrush" Value="#D0D1D7" />
                                <Setter TargetName="shortcutbutton" Property="Opacity" Value="1" />
                                <Setter TargetName="shortcutbutton" Property="BorderThickness" Value="1 1 0 0" />
                                <Setter TargetName="shortcutbutton" Property="Cursor" Value="Hand" />
                                <!--<Setter TargetName="Border" Property="Foreground" Value="#45619D\#2F477A" />-->
                            </Trigger>
                            <Trigger Property="IsPressed" Value="true">
                                <Setter TargetName="shortcutbutton" Property="Background" Value="#FFFFFF" />
                                <Setter TargetName="shortcutbutton" Property="BorderBrush" Value="#D0D1D7" />
                                <Setter TargetName="shortcutbutton" Property="BorderThickness" Value="1 1 0 0" />
                                <Setter TargetName="shortcutbutton" Property="Cursor" Value="Hand" />
                                <!--<Setter TargetName="Border" Property="Foreground" Value="Red" />-->
                            </Trigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter TargetName="shortcutbutton" Property="Background" Value="#F4F4F4" />
                                <Setter TargetName="shortcutbutton" Property="BorderBrush" Value="#D0D1D7" />
                                <Setter TargetName="shortcutbutton" Property="BorderThickness" Value="0 0 0 0" />
                                <Setter TargetName="shortcutbutton" Property="Cursor" Value="Wait" />
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
            <Setter Property="Control.Margin" Value="2"></Setter>
            <Setter Property="Control.Foreground" Value="#2F477A"></Setter>
            <Setter Property="Control.BorderBrush" Value="{x:Null}"></Setter>
            <EventSetter Event="Button.Click" Handler="Button_Click" />
        </Style>
        <Style x:Key="ButtonStyleOn">
            <Setter Property="Control.Template">
                <Setter.Value>
                    <ControlTemplate TargetType="Button">
                        <Border Name="shortcutbutton"  
                    BorderThickness="0 0 0 0"
                    BorderBrush="#D0D1D7"
                    Background="#DCEAF9">
                            <ContentPresenter Margin="2" 
                                  HorizontalAlignment="Center"
                                  VerticalAlignment="Center" 
                                  RecognizesAccessKey="True"/>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsMouseOver" Value="true">
                                <Setter TargetName="shortcutbutton" Property="Background" Value="#DCEAF9" />
                                <Setter TargetName="shortcutbutton" Property="BorderBrush" Value="#D0D1D7" />
                                <Setter TargetName="shortcutbutton" Property="Opacity" Value="1" />
                                <Setter TargetName="shortcutbutton" Property="BorderThickness" Value="1 1 0 0" />
                                <Setter TargetName="shortcutbutton" Property="Cursor" Value="Hand" />
                                <!--<Setter TargetName="Border" Property="Foreground" Value="#45619D\#2F477A" />-->
                            </Trigger>
                            <Trigger Property="IsPressed" Value="true">
                                <Setter TargetName="shortcutbutton" Property="Background" Value="#DCEAF9" />
                                <Setter TargetName="shortcutbutton" Property="BorderBrush" Value="#D0D1D7" />
                                <Setter TargetName="shortcutbutton" Property="BorderThickness" Value="1 1 0 0" />
                                <Setter TargetName="shortcutbutton" Property="Cursor" Value="Hand" />
                                <!--<Setter TargetName="Border" Property="Foreground" Value="Red" />-->
                            </Trigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter TargetName="shortcutbutton" Property="Background" Value="#F4F4F4" />
                                <Setter TargetName="shortcutbutton" Property="BorderBrush" Value="#D0D1D7" />
                                <Setter TargetName="shortcutbutton" Property="BorderThickness" Value="1 1 0 0" />
                                <Setter TargetName="shortcutbutton" Property="Cursor" Value="Wait" />
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>

then later in the code...

            buttonOff = (System.Windows.Media.Brush)FindResource("ButtonBrush");

            OptionList.Visibility = System.Windows.Visibility.Collapsed;
            
            List<Button> list = new List<Button>();
            list.Clear();
            Button ib = new Button();
            ib.Style = (Style)FindResource("OptionButtonStyle");
            ib.Tag = "1";
            ib.Background = buttonOff;

[Shaggy Hiker]

I've been getting into WPF more and more with this project. Putting things in XAML is a different way of thinking about things. When I asked the question, I didn't even know about Windows.Resources in XAML. I've done more with that, by now, but I hadn't yet encountered the idea of putting brushes in there.