(Related) I have found here, here, and here are questions describing a related problem of ZXingBarcodeImageView rendering a blurry QR code in Xamarin Forms - but they have not lead to a solution for my problem.
The Problem
I am using ZXing to draw and display a QR Code in Xamarin forms, but the QR code it produces is blurry.
The reason is in the .xaml page I am setting the ZXingBarcodeImageView properties WidthRequest=300 and HeightRequest=300. This is stretching the QR code after it is drawn by the ZXing library:
<forms:ZXingBarcodeImageView
IsVisible="True"
x:Name="QRCodeView"
BarcodeFormat="QR_CODE"
HeightRequest="300" //Stretching Height
WidthRequest="300" //Stretching Width
BarcodeValue="-1"
/>
This question's top answer suggests binding the attributes Height and Width ahead of time but no matter how I change the parameters in the BarcodeOptions array it suggests, the QR code stays the same.
How do I change to the setup dimensions of the ZXingBarcodeImageView before drawing time to avoid the stretching?
Adding the BarcodeOptions to the ZXingBarcodeImageView in XAML seems to work in my case. The same when binding from code, as suggested in one of your linked solutions, does not work for some reason.
<ContentPage .... xmlns:zxcm="clr-namespace:ZXing.Common;assembly=zxing.portable">
<forms:ZXingBarcodeImageView
IsVisible="True"
x:Name="QRCodeView"
BarcodeFormat="QR_CODE"
HeightRequest="300"
WidthRequest="300"
BarcodeValue="-1">
<zx:ZXingBarcodeImageView.BarcodeOptions>
<zxcm:EncodingOptions Width="300" Height="300" />
</zx:ZXingBarcodeImageView.BarcodeOptions>
</forms:ZXingBarcodeImageView>
</ContentPage>
A sample project can be found here: https://github.com/jfversluis/Blurry-ZXingBarcodeImageView
Related
In my login UI, I have a footer image, which is showing perfectly in small devices. But on big screen devices (mainly on iPad) it is not showing fully.
I tried all Aspect property of Image, but not worked.
Screenshot:
I try a lot to fix this but didn't get a solution.
Attaching the LoginPage.xaml file with this question. Please suggest a solution for this issue. :)
Make sure (in the iOS project -> Assets) your image set has 3 different sizes xxx.png,xxx.png#2x and xxx.png#3x .
Which image will be used for your app? That depends on the device your app is viewed on. Higher resolution devices (larger and newer devices) have more pixels on their screens. Thus they need higher resolution images to display properly without any blurring.
If you don’t supply the higher resolution (#2x or #3x) images, your app will automatically try to scale the #1x image up. This is not good and can result in a distorted or blurry image!
Based on the file you linked in the comments, I think it would suffice to remove the bottom StackLayout wrapping the Image, and instead put Grid.Row="1" & VerticalOptions="End" to the bottom Image.
Please update your question with the relevant code to make the question and answers more helpful to others.
Remove latest StackLayout with image and add it after StackLayout with Grid.Row="1" like this
<Grid Grid.Row="1"
BackgroundColor="#c0eefb">
<Image
Source="ic_footer_image_xx.png"
Aspect="AspectFill"
HorizontalOptions="FillAndExpand"/>
</Grid>
Is it good to use margin/padding to align the position of CachedImage in XAML Xamarin Forms? Or any other preferable/good way to align it so that it can stay consistant to all devices screens?
Like for example:
There are plenty of options, which to use will depend on the rest of your layout. Anyway, increasing the transparent area of the image will not port very well, because of different screen-sizes and -ratios.
Learn about layouts in Xamarin.Forms, it will help you much. On way to center (or otherways align) an image would be to use an AbsoluteLayout (see here)
<AbsoluteLayout HorizontalOptions="Fill" VerticalOptions="Fill">
<Image Source="whatever.png"
AbsoluteLayout.LayoutFlags="PositionProportional"
AbsoluteLayout.LayoutBounds=".5,.5,-1,-1" />
</AbsoluteLayout>
AbsoluteLayout.LayoutBounds=".5,.5,-1,-1" sets the position of the Image to centered, while the size is retained.
I have decided to try Xamarin Forms, because I thought that I can make one design for all platforms or at least Android and iOS.
However a simple form like:
<?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:app91="clr-namespace:App9;assembly=MasterDetail.Android"
x:Class="MasterDetail.CompetitorsListPage"
>
<StackLayout>
<Label Text="{Binding CurrentEvent.Name}"></Label>
<StackLayout Orientation="Horizontal">
<Button Text="By Place" Clicked="Button_OnClickedByPlace"></Button>
<Button Text="By Number" Clicked="Button_OnClickedByNumber"></Button>
<Button Text="By Rating" Clicked="Button_OnClickedByRating"></Button>
<Button Text="Change Event" Clicked="Button_OnClickedChangeEvent"></Button>
</StackLayout>
<ScrollView>
<ListView x:Name="couples" ItemSelected="Comps_OnItemSelected" ItemTapped="Couples_OnItemTapped">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.View>
<StackLayout Orientation="Horizontal">
<Label Text="{Binding Round}"></Label>
<Label Text="{Binding Pos, StringFormat='({0}).'}"></Label>
<Label Text="{Binding Name}"></Label>
<Label Text="{Binding StartingNumber}" ></Label>
<Label Text="{Binding OldRating, StringFormat=' [{0}]'}"></Label>
<!--<Label Text="{Binding NewRating, StringFormat=' {0} ]'}"></Label>-->
</StackLayout>
</ViewCell.View>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ScrollView>
</StackLayout>
</ContentPage>
Looks completely different on Android and iOS. I do not mind colours, but font size? I do not set font anywhere in the code or xaml.
Any idea what am I doing wrong?
Here it is a picture showing both versions:
This is by design. Forms is intended to provide a native experience on each platform by using their respective UI standards. Android has a different default color scheme than iOS. iOS default buttons look different than Android.
You can override the default fonts, sizes, colors, etc if you like in order to provide a more consistent UI. Xamarin has also introduced Themes for Forms which help you provide a consistent UI between platforms.
Because Android has variety of screen sizes and different screen DPI as compared to standard dpi and font sizes across iOS devices, it is not possible to create same look. But you can certainly change Theme in the MainActivity of your Droid project and increase font size as per your convenience. Beware that your theme's font size may be too big for small devices and too small for big devices. You can add scaling factor for font size in your theme, but I have not been very successful, instead, I tried to design a UI that will automatically fit for the best.
As per Xamarin Evolve 2016, some questions were raised regarding font sizes, they said it is difficult, but they are trying to make some unified font sizing.
Although Xamarin.Forms has everything in Xaml and C#, you still need to use iOS assets and Android resources to customize look and feel.
For me, #Jason's answer and comments from #Egg and #Bill Reiss are spot-on.
Meanwhile, so often clients request "same font size" across platforms that something like this finds its way into base Styles or Theme to account for what seems to be "natively smaller" fonts on Android:
<OnPlatform x:TypeArguments="Font">
<OnPlatform.iOS>Bold,Medium</OnPlatform.iOS>
<OnPlatform.Android>Bold,Large</OnPlatform.Android>
<OnPlatform.WinPhone>Bold,Medium</OnPlatform.WinPhone>
</OnPlatform>
Something similar can also be expressed in code at or near app startup, for example as a base Label font added to global Styles dictionary.
Just wanted to give a concrete example of what others above alluded to.
Strange behavior on iOS - as you can see those are labels in StackLayout, while in Android they behave OK, in iOS second and third label behave more lithe they were in some kind of grid rather than stack –
You have put 5 labels in a horizontal stack, and haven't changed the layout options on any of them. This will 'stack' all 5 labels next to each other, then size them based on the amount of text to be displayed. There is not enough horizontal space to accommodate all of the text, so the labels are wrapping vertically. The longest labels show the most wrapping, but as they get longer other labels wrap as well, which is why the Pos and OldRating data raps in some labels. When I'm working out layouts like this I often add different background colors to each control so I can see how they are laying out.
There are different ways to solve this depending on your desired result. If you want the entire line of text to wrap you can concatenate the data behind the scenes and add it as one label. If you want the name to wrap and the other data to display without wrapping you can set WidthRequests on the labels.
I am using VS2013, Windows 8.1 and developing a windows store app.
Im creating a simple contacts - listview, that displays the contact details along with contact image within an ellipse. When I click on the listview item, I want to display the contact details on right side of the page. Now the issue I am facing is, I am not able to fit the contact image to the right size on the ellipse on the right side pane.
I am able to achieve it in my list view since its an smaller ellipse.
Important: I do not want the image to look stretched/Zoomed in /Zoomed out. It should exactly look like how it appears within the list view. (For list view , I have used Ellipse.Fill along with Imagebrush, but relatively smaller sized ellipse)
What I tried so far:
Ellipse.Fill property which paints the image to size, but the image looks stretched.
I tried setting "Stretch" property within the image tag within ellipse, but did not work.
I tried Image.clip, but I do not have "EllipseGeometry" option, instead only RectangleGeometry.
Lastly I created an image that has a transparent center and I place this frame over the contact image like a mask. This works well on some resolutions. But when some other resolution, the contact images which are binded from backend, go beyond the frame, although I set "MaxHeight" or "Height" properties.
I want to do it the right way, since I feel adding an image mask might not be a great way to achieve this. Please help!
I tried this for listview, n works fine, But the same code for right pane looks stretched (I have tried removing stretch attirbute, or tried other options like Stretch ="None" /"Uniform" etc )
I have attached screenshot.
Since code isn't clearly mentioned, you can do it with both Ellipse and Border. Here's the code snippet
<!--With Ellipse-->
<Ellipse Height="200"
Width="200">
<Ellipse.Fill>
<ImageBrush Stretch="Uniform"
ImageSource="Assets/profile.png" />
</Ellipse.Fill>
</Ellipse>
<!--With Border-->
<Border Height="200"
Width="200"
CornerRadius="150">
<Border.Background>
<ImageBrush Stretch="Uniform"
ImageSource="Assets/profile.png" />
</Border.Background>
</Border>
Here's the result
The properties "AlignmentX AlignmentY" within ImageBrush solved my issue.
If your image has portrait orientation, then you can use Stretch, AlignmentX, AlignmentY properties of ImageBrush like this to achieve best preview result
<Border CornerRadius="20" BorderThickness="1" BorderBrush="DarkGoldenrod">
<Ellipse Width="40" Height="40">
<Ellipse.Fill>
<ImageBrush ImageSource="{Binding PractitionerPhoto}" Stretch="UniformToFill" AlignmentX="Center" AlignmentY="Top" />
</Ellipse.Fill>
</Ellipse>
</Border>
I have an image as a drawing brush in xaml. The only property set is Stretch, which is set to Uniform.
The image is then set to the background of a usercontrol which has no properties set with regards to size.
The usercontrol is then used within a a grid, and set to span 2 rows like so:
<common:Logo
Height="130"
Width="500"
Grid.Column="0"
Grid.Row="0"
Grid.RowSpan="2"
HorizontalAlignment="Left"
/>
The problem is that there is loads of white space on top and below the image, which is also quite small.
The image started as a vector graphic and has no space above or below.
When I view the usercontrol with sizes set, it fits perfectly with no white space.
I am hoping this is not a problem with the grid reporting an incorrect size.
Any ideas would be appreciated!
Visual Studio was not refreshing any of the changes, running the code and reviewing what was produced fixed the whole problem!