Samples for the Xamarin Svg enterprise cross platform and full featured Svg image control

This repository holds the samples for the XamSvg Xamarin control.

Xamarin.Forms (Android, iOS, UWP) Xamarin Native (Android, iOS, UWP)
NuGet NuGet

Xamarin Forms controls:
SvgImageSource
SvgImage

Xamarin Android controls:
SvgImageView
SvgPictureDrawable

Xamarin iOS controls:
UISvgImageView

Native UWP controls:
Svg

More infos

Quick start for Xamarin Forms

  1. Tell XamSvg where to search for svg files

Svg files will be stored as embedded resources. To access an embedded resource the code needs the full assembly path of this resource. To make this process easier, you tell XamSvg in which assembly to search for the resources and you don't specify the full path of the svg file in the Svg control.

public class App : Application
{
    public App()
    {
        XamSvg.Shared.Config.ResourceAssembly = typeof(App).Assembly;
        ...
    }
...

Trick: you can add more than one assembly by using the ResourceAssemblies property instead.

  1. Add your svg files

Create a folder "images" at the root of your netstandard project (the project containing the App.cs file) and put your svg files there.
Make sure they have the .svg extension. And set their build action type to embedded resource (important!).

  1. Use an SvgImage control
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:svg="clr-namespace:XamSvg.XamForms;assembly=XamSvg.XamForms"
             x:Class="XamSvg.Demo.MainPage">
  <ContentView>
    <StackLayout Orientation="Vertical" VerticalOptions="Start">

        <svg:SvgImage Svg="res:images.logo" HorizontalOptions="Start" HeighRequest="32" />

        <svg:SvgImage Svg="res:images.logo" HorizontalOptions="Start" HeighRequest="32"
                      ColorMapping="{Binding ColorMapping}" 
                      ColorMappingSelected="ffffff=00ff00;000000=0000FF" 
                      />

    </StackLayout>
  </ContentView>
</ContentPage>

Remarks:

  • The xmlns:svg attribute is required on the ContentPage. If you use Resharper, it will be added automagically.
  • The Svg property value is the image name. It is prefixed with res: (which means the svg file is searched in embedded resources), its extension (.svg) is optional. images is the folder in which you put the svg file.
  • All properties are bindable.

Another scheme string: can be used to load an inline svg. Simply put the svg string after string:.

image.png

  1. Enjoy

Color Mapping

XamSvg supports remapping color based on a change in the control's state, like selected or disabled.

To specify a color mapping, set the ColorMapping, ColorMappingSelected or ColorMappingDisabled properties to a string. This string contains a list of mapping separated by a semicolumn ";". A mapping has two parts, separated by the equal sign. The left part is the color that should be replaced by the right part.

A color is specified using standard html coding: AARRGGBB, RRGGBB, or RGB. A is the transparency (alpha channel).

For example ffffff=00ff00;000000=0000FF means replace ffffff (white) by 00ff00 (green) and replace 000000 (black) by 0000FF (red).

Xamarin Forms samples

Simple svg image

   <svg:SvgImage Svg="res:images.logo" HeightRequest="70" HorizontalOptions="Center" VerticalOptions="Center" />

Svg image on a button

  <Button Text="Add Contact" ContentLayout="Right,20">
     <Button.ImageSource>
         <svg:SvgImageSource Svg="res:images.tabHome" Height="60" ColorMapping="000000=FF0000" />
     </Button.ImageSource>
  </Button>

Svg image for the icon of a TabbedPage tab

  <NavigationPage Title="Home">
    <x:Arguments>
        <views:HomePage />
    </x:Arguments>
    <NavigationPage.IconImageSource>
        <svg:SvgImageSource Svg="res:images.tabHome" Height="50" />
    </NavigationPage.IconImageSource>
  </NavigationPage>

Common mistakes

If nothing appears, make sure your svg is displayed correctly by the windows explorer (after you installed this extension).

Common errors include

  • forgetting to set the build action of the svg file to "Embedded resource".
  • missing viewBox attribute at the root of the svg file (open it using a text editor).
  • the svg color is the same as the background color, especially white or black. Use ColorMapping to change colors, or edit your svg file with inkscape or your preferred text editor.

The assembly in which the svg resources are must have an assembly Name equal to its Default namespace, otherwise the svg files will not be found. If you are unable to do so, you can still display an svg but you will have to specify the full name of the resource like this:

    <xamForms:SvgImage
        Svg="res:YourDefaultNamespace.Images.getFDR_01_Ready.svg"
        x:Name="SvgIcon" HorizontalOptions="Fill" VerticalOptions="Start" Margin="8,0,8,0" BackgroundColor="Yellow"
        />

You can discover the full name of an embedded resource by opening your assembly (.dll in your bin folder) in the free tool Telerik JustDecompile.

image.png

Other Receipes

Icons on TabbedPage

<?xml version="1.0" encoding="utf-8" ?>
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:views="clr-namespace:XamSvg.Demo;assembly=XamSvg.Demo"
             xmlns:svg="clr-namespace:XamSvg.XamForms;assembly=XamSvg.XamForms"
             x:Class="XamSvg.Demo.Pages.TabContainer"
             Title="Vapolia.fr XamSvg Demo"
            >

  <views:HomePage Title="Home">
    <views:HomePage.IconImageSource>
        <svg:SvgImageSource Svg="res:images.tabHome" />
    </views:HomePage.IconImageSource>
  </views:HomePage>
    
</TabbedPage>

Mvvmcross

The library is fully compatible with mvvmcross bindings for all properties:
image source, color mappings, and all others.

Android native: make the svg image height the same height of a Button

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 
              xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:app="http://schemas.android.com/apk/res-auto"
              xmlns:tools="http://schemas.android.com/tools"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <Button
        android:id="@+id/myinfo"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="@string/Menu_MyInfo"
        style="@style/Widget.AppCompat.Button.Borderless"
        app:MvxBind="Click SettingsCommand"
        />
    <XamSvg.SvgImageView
        app:layout_constraintTop_toTopOf="@+id/myinfo"
        app:layout_constraintBottom_toBottomOf="@+id/myinfo"
        app:layout_constraintLeft_toLeftOf="parent"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        tools:layout_width="30dp"
        app:colorMapping="000000=e01a1a"
        app:colorMappingSelected="000000=ff3030"
        app:colorMappingDisabled="000000=1a1a1a"
        app:fillMode="fit"
        app:svg="res:images.info" />

Note that as the svg has an intrinsic width computed from its height and its aspect ratio, the width displayed by the designer is incorrect. You can correct the designer by assigning a design time only value to layout_width using the tools prefix: tools:layout_width="30dp" which requires the xmlns:tools namespace declaration.

Android native: set back button toolbar icon

var toolbar = FindViewById<Toolbar>(Resource.Id.toolbar);
toolbar.NavigationIcon = SvgFactory.GetDrawable("res:images.webbrowser.backward", "000000=FFFFFF");

iOS storyboard: usage in an xcode storyboard

Using Visual Studio Mac, open your storyboard file using Open with xcode. Add an Image view (UIImageView), set its custcom Class property to UISvgImageView, and optionally add new User Defined Runtime Attributes as required:

Attribute Inspector

Key Path Type Sample Value
BundleName String res:images.info
ColorMapping String 000000=e01a1a
ColorMappingSelected String 000000=ff3030

To size your svg, set contraints on one dimension only. The other dimension will be set using the first dimension and the computed aspect ratio. If you set constraints on both dimensions, the svg will stretch. You can prevent this by setting FillMode to Fit (along with ContentMode to AspectFit):

Key Path Type Sample Value
FillMode String Fit

When only one dimension is constrained, the designer don't know how to set the other dimension and displays contraint errors. The solution is to set the intrinsic size to a manual value in the dimension which has no contraint (in the dimension property pane of the designer).

Intrinsic Size

  1. Select the UISvgImageView view.
  2. Show the size inspector (⌘Shift5).
  3. Change the "Intrinsic Size" drop-down from "Default (System Defined)" to "Placeholder."
  4. Enter reasonable guesses at your view's runtime width or height. Width if you set contraints on the height, height otherwise.

These constraints are removed at compile-time, meaning they will have no effect on your running app, and the layout engine will add constraints as appropriate at runtime to respect your view's intrinsicContentSize.

Reference

Xamarin Forms

Default namespace:

xmlns:svg="clr-namespace:XamSvg.XamForms;assembly=XamSvg.XamForms"

SvgImage control

SvgImage displays a image in up to 2 states: normal, selected

<svg:SvgImage Svg="res:images.union" HeightRequest="70" HorizontalOptions="Center" VerticalOptions="Center" />
Property Type Notes
Svg string svg to display. Don't forget the res: prefix if loading from embedded resources
ColorMapping string see color mapping reference. Default to none.
ColorMappingSelected string color mapping when IsSelected="True". Default to none.
IsSelected bool used to switch color mapping
IsSelectionEnabled bool True by default: the value of IsSelected is also inherited from the parent container
Command ICommand if set, execute this command on tap
CommandParameter object parameter to send when calling Command.Execute
Width double Optional. You can also specify the width only and height will be computed from the aspect ratio
Height double Optional
FillMode FillMode Fit, Fill, Crop. Useful only if both width and height are forced. Default to Fit to maintain the aspect ratio.
IsLoadAsync bool set to False to disable async image loading, making the image appear immediatly. Default to True.
IsHighlightEnabled bool if set, ColorMappingSelected is used while the image is pressed (until the finger is released)
ViewportTransform IMatrix transform the svg using any matrix before displaying it

SvgImageSource class

SvgImageSource inherits from ImageSource, use it on any ImageSource property. For example Page.IconImageSource. It can also be transformed into a FileImageSource by calling CreateFileImageSource().

<svg:SvgImageSource Svg="res:images.tabHome" Height="50" />
Property Type Notes
Svg string svg to display. Don't forget the res: prefix if loading from embedded resources.
Width double Optional. You can also specify the width only and height will be computed from the aspect ratio.
Height double Optional.
ColorMapping string Optional. See color mapping reference.
SvgFillMode FillMode Fit, Fill, Crop. Useful only if both width and height are forced. Default to Fit to maintain the aspect ratio.
PreventTintOnIos bool Default to false. Prevents tinting on iOS, thus always displaying the original image.

Android native

Layout properties:

Tag Type Default value Notes
app:svg string or resource id (required) .net embedded resource file path and name, or android resource id
app:colorMapping string (null) example: FF000000=FF808080
app:colorMappingSelected string (null) example: FF000000=FFa0a0a0;FFFFFFFF=00000000
app:colorMappingDisabled string (null)
app:traceEnabled bool false
app:loadAsync bool true
app:fillMode enum fit fit, fill of fit_crop (new v3.1.0). fit_crop: Scale the image uniformly (maintain the image's aspect ratio) so that both dimensions (width and height) of the image will be equal to or larger than the corresponding dimension of the view (minus padding).
android:adjustViewBounds bool true if true and fillMode is not Fill, the svg view will grow or shrink depending on the svg size.
android:autoMirrored bool false true to mirror image in RTL languages

android:padding is respected, and included in the width/height measurement.
android:gravity is respected, and included in the width/height measurement. If the svg is smaller than its view, this property controls its centering.

iOS native

UISvgImageView inherits UIImageView, so it's easy to use it in an xcode storyboard: drag an UIImageView and set its custom class to UISvgImageView. To set specific svg properties, add User Defined Runtime Attributes in the same pane where you set the custom class.

Attributes (supported in User Defined Runtime Attributes):

Key Path Type Default value Notes
BundleName string (required) Svg path. Example: res:images.logo
BundleString string (optional) exclusive with BundleName. The svg content as a string.
ColorMapping string (null) example: FF000000=FF808080
ColorMappingSelected string (null) example: FF000000=FFa0a0a0;FFFFFFFF=00000000
TraceEnabled bool false
IsLoadAsync bool true set to false to force the svg to appear immediatly, or if it disappears sometimes
AlignmentMode string TopLeft TopLeft, CenterHorizontally, CenterVertically, Center. Can be combined (in code only).
FillMode string Fit Fit, Fill, FitCrop.
FillWidth number 0 The width the svg would like to have. 0 to let the OS decides using UI constraints or Frame value.
FillHeight number 0 The height the svg would like to have. 0 to let the OS decides using UI constraints or Frame value.

UIImageView.ContentMode is forced by UISvgImageView, so it has no impact. Use FillMode instead.


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