Aspose.HTML for .NET 24.10 – Improving Rendering Quality

Aspose.HTML for .NET 24.10

In version 24.10, Aspose.HTML introduced updates to the public API, aimed primarily at enhancing support for Linux environments. These updates include replacing several enumerations from System.Drawing with implementations within Aspose’s own Aspose.Html.Drawing and Aspose.Html.Rendering.Image namespaces:

• The FontStyle system enumeration was replaced with WebFontStyle one.
• The SmoothingMode system enumeration was replaced with ImageRenderingOptions.UseAntialiasing property.
• The TextRenderingHint system enumeration was replaced with TextOptions.UseHinting property.

FontStyle Vs WebFontStyle

In version 24.10, the FontStyle enumeration, which specifies font styles like regular, bold, and italic, has been replaced by the WebFontStyle enumeration:

Old	New
FontStyle.Bold	WebFontStyle.Bold
FontStyle.Italic	WebFontStyle.Italic
FontStyle.Regular	WebFontStyle.Regular

Accordingly, in the GraphicContext class, the FontStyle property type has changed:

namespace Aspose.Html.Rendering
{
    public class GraphicContext
    { 
        //From:
        public virtual FontStyle FontStyle { get; set; }
 
        //To:
        public virtual WebFontStyle FontStyle { get; set; }
    }
}

SmoothingMode and TextRenderingHint Vs UseAntialiasing and UseHinting

In version 24.10,

• the SmoothingMode system enumeration, previously used to control the antialiasing quality of rendered shapes and images, has been replaced by the ImageRenderingOptions.UseAntialiasing property;
• the TextRenderingHint system enumeration, which helps control text rendering quality, has now been replaced by the TextOptions.UseHinting property. This property maintains the clarity and readability of text.

The сorrespondence table below guides how rendering settings are applied when migrating between old and new versions of Aspose.HTML for .NET.

Correspondence Table for Different Rendering Cases

The table provides clear guidance, indicating how UseAntialiasing and UseHinting settings correspond to older properties like SmoothingMode and TextRenderingHint:

UseAntialiasing	UseHinting	SmoothingMode	TextRenderingHint
true	true	SmoothingMode.AntiAlias	TextRenderingHint.AntiAliasGridFit
false	true	SmoothingMode.None	TextRenderingHint.SingleBitPerPixelGridFit
true	false	SmoothingMode.AntiAlias	TextRenderingHint.AntiAlias
false	false	SmoothingMode.None	TextRenderingHint.SingleBitPerPixel

This table shows how to convert previous anti-aliasing and text rendering settings to the new UseAntialiasing and UseHinting properties. Here’s how you can interpret and apply this table:

1. When you decide on the required level of text clarity and shape rendering for your project, match the previous settings to the new properties.
2. Replace the old SmoothingMode and TextRenderingHint values with the corresponding UseAntialiasing and UseHinting settings.

For example, if your previous configuration used SmoothingMode.AntiAlias and TextRenderingHint.AntiAliasGridFit, switch to UseAntialiasing = true and UseHinting = true.

This is the example we will consider below.

Using SmoothingMode and TextRenderingHint Enumerations – 24.9 and Earlier Versions

This C# code snippet demonstrates how to render HTML content to an image file using Aspose.HTML for .NET with old dependencies of System.Drawing, specifically configuring the output to optimize rendering quality with anti-aliasing options:

using System.IO;
using Aspose.Html;
using Aspose.Html.Rendering.Image;
using System.Drawing.Drawing2D;
using System.Drawing.Text;
...
    // Create an instance of the ImageRenderingOptions class to specify rendering quality
    var opt = new ImageRenderingOptions
    {
        SmoothingMode = SmoothingMode.AntiAlias,
        Text =
        {
            TextRenderingHint = TextRenderingHint.AntiAliasGridFit
        }
    };

    // Create an HTML Document
    using (var doc = new HTMLDocument("text", string.Empty))
    // Create an ImageDevice object
    using (var device = new ImageDevice(opt, "out-old.png"))
    {
        // Rendering HTML to image
        doc.RenderTo(device);
    }

Using new UseAntialiasing and UseHinting properties – Since Version 24.10

The following code demonstrates rendering HTML content to an image file using the new UseAntialiasing and UseHinting properties. This example is the same as the previous example, where were used the system SmoothingMode and TextRenderingHint enumerations:

using System.IO;
using Aspose.Html;
using Aspose.Html.Rendering.Image;
...
    // Create an instance of the ImageRenderingOptions class
    var opt = new ImageRenderingOptions
    {
        UseAntialiasing = true,
        Text =
        {
            UseHinting = true
        }
    };

    // Create an HTML Document
    using (var doc = new HTMLDocument("text", string.Empty))
    // Create an ImageDevice object
    using (var device = new ImageDevice(opt, "out-new.png"))
    {
        // Rendering HTML to image
        doc.RenderTo(device);
    }

Conclusions

• The migration to WebFontStyle enumeration, UseAntialiasing, and UseHinting properties in Aspose.HTML for .NET 24.10 represents a step forward in supporting Linux environments.
• The base values of the UseAntialiasing and UseHinting properties have been changed, resulting in better text rendering when using the default options.
• As part of the move to Linux support, this migration also aims to unify the public API to simplify access to the different versions of the Aspose.HTML for .NET library that support different HTML rendering engines.

Thus, the API changes implemented in the 24.10 release greatly affect the quality of text and image display, make it easier for users to switch between different versions of the Aspose.HTML libraries for .NET that support different HTML rendering engines, and are steps forward in Linux support.

Aspose.HTML for .NET 24.10 Release Notes – This release includes changes to the public API related to improving Linux support, rendering quality, and fixing bugs to enhance the library’s overall performance and stability.