Class HtmlContainer

Low level handling of Html Renderer logic, this class is used by TheArtOfDev.HtmlRenderer.Core.Parse.HtmlParser and HtmlRender.

Inheritance

System.Object

HtmlContainer

Inherited Members

System.Object.ToString()

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

Namespace: TheArtOfDev.HtmlRenderer.WinForms

Assembly: Telerik.WinControls.RadMap.dll

Syntax

public sealed class HtmlContainer : IDisposable

Constructors

HtmlContainer()

Init.

Declaration

public HtmlContainer()

Properties

ActualSize

The actual size of the rendered html (after layout)

Declaration

public SizeF ActualSize { get; }

Property Value

System.Drawing.SizeF

AvoidAsyncImagesLoading

Gets or sets a value indicating if image asynchronous loading should be avoided (default - false).
True - images are loaded synchronously during html parsing.
False - images are loaded asynchronously to html parsing when downloaded from URL or loaded from disk.

Declaration

public bool AvoidAsyncImagesLoading { get; set; }

Property Value

System.Boolean

Remarks

Asynchronously image loading allows to unblock html rendering while image is downloaded or loaded from disk using IO ports to achieve better performance.
Asynchronously image loading should be avoided when the full html content must be available during render, like render to image.

AvoidGeometryAntialias

Gets or sets a value indicating if anti-aliasing should be avoided for geometry like backgrounds and borders (default - false).

Declaration

public bool AvoidGeometryAntialias { get; set; }

Property Value

System.Boolean

AvoidImagesLateLoading

Gets or sets a value indicating if image loading only when visible should be avoided (default - false).
True - images are loaded as soon as the html is parsed.
False - images that are not visible because of scroll location are not loaded until they are scrolled to.

Declaration

public bool AvoidImagesLateLoading { get; set; }

Property Value

System.Boolean

Remarks

Images late loading improve performance if the page contains image outside the visible scroll area, especially if there is large amount of images, as all image loading is delayed (downloading and loading into memory).
Late image loading may effect the layout and actual size as image without set size will not have actual size until they are loaded resulting in layout change during user scroll.
Early image loading may also effect the layout if image without known size above the current scroll location are loaded as they will push the html elements down.

CssData

the parsed stylesheet data used for handling the html

Declaration

public CssData CssData { get; }

Property Value

CssData

IsContextMenuEnabled

Is the build-in context menu enabled and will be shown on mouse right click (default - true)

Declaration

public bool IsContextMenuEnabled { get; set; }

Property Value

System.Boolean

IsSelectionEnabled

Is content selection is enabled for the rendered html (default - true).
If set to 'false' the rendered html will be static only with ability to click on links.

Declaration

public bool IsSelectionEnabled { get; set; }

Property Value

System.Boolean

Location

The top-left most location of the rendered html.
This will offset the top-left corner of the rendered html.

Declaration

public PointF Location { get; set; }

Property Value

System.Drawing.PointF

MaxSize

The max width and height of the rendered html.
The max width will effect the html layout wrapping lines, resize images and tables where possible.
The max height does NOT effect layout, but will not render outside it (clip).
ActualSize can be exceed the max size by layout restrictions (unwrappable line, set image size, etc.).
Set zero for unlimited (width\height separately).

Declaration

public SizeF MaxSize { get; set; }

Property Value

System.Drawing.SizeF

ScrollOffset

The scroll offset of the html.
This will adjust the rendered html by the given offset so the content will be "scrolled".

Declaration

public Point ScrollOffset { get; set; }

Property Value

System.Drawing.Point

Examples

Element that is rendered at location (50,100) with offset of (0,200) will not be rendered as it will be at -100 therefore outside the client rectangle.

SelectedHtml

Copy the currently selected html segment with style.

Declaration

public string SelectedHtml { get; }

Property Value

System.String

SelectedText

Get the currently selected text segment in the html.

Declaration

public string SelectedText { get; }

Property Value

System.String

UseGdiPlusTextRendering

Use GDI+ text rendering to measure/draw text.

Declaration

public bool UseGdiPlusTextRendering { get; set; }

Property Value

System.Boolean

Remarks

GDI+ text rendering is less smooth than GDI text rendering but it natively supports alpha channel thus allows creating transparent images.

While using GDI+ text rendering you can control the text rendering using System.Drawing.Graphics.TextRenderingHint, note that using System.Drawing.Text.TextRenderingHint.ClearTypeGridFit doesn't work well with transparent background.

Methods

ClearSelection()

Clear the current selection.

Declaration

public void ClearSelection()

Dispose()

Declaration

public void Dispose()

Implements

System.IDisposable.Dispose()

GetAttributeAt(Point, String)

Get attribute value of element at the given x,y location by given key.
If more than one element exist with the attribute at the location the inner most is returned.

Declaration

public string GetAttributeAt(Point location, string attribute)

Parameters

System.Drawing.Point location the location to find the attribute at

System.String attribute the attribute key to get value by

Returns

System.String found attribute value or null if not found

GetElementRectangle(String)

Get the rectangle of html element as calculated by html layout.
Element if found by id (id attribute on the html element).
Note: to get the screen rectangle you need to adjust by the hosting control.

Declaration

public RectangleF? GetElementRectangle(string elementId)

Parameters

System.String elementId the id of the element to get its rectangle

Returns

System.Nullable<System.Drawing.RectangleF> the rectangle of the element or null if not found

GetHtml(HtmlGenerationStyle)

Get html from the current DOM tree with style if requested.

Declaration

public string GetHtml(HtmlGenerationStyle styleGen = HtmlGenerationStyle.Inline)

Parameters

HtmlGenerationStyle styleGen Optional: controls the way styles are generated when html is generated (default: Inline)

Returns

System.String generated html

GetLinkAt(Point)

Get css link href at the given x,y location.

Declaration

public string GetLinkAt(Point location)

Parameters

System.Drawing.Point location the location to find the link at

Returns

System.String css link href if exists or null

GetLinks()

Get all the links in the HTML with the element rectangle and href data.

Declaration

public List<LinkElementData<RectangleF>> GetLinks()

Returns

System.Collections.Generic.List<LinkElementData<System.Drawing.RectangleF>> collection of all the links in the HTML

HandleKeyDown(Control, KeyEventArgs)

Handle key down event for selection and copy.

Declaration

public void HandleKeyDown(Control parent, KeyEventArgs e)

Parameters

System.Windows.Forms.Control parent the control hosting the html to invalidate

System.Windows.Forms.KeyEventArgs e the pressed key

HandleMouseDoubleClick(Control, MouseEventArgs)

Handle mouse double click to select word under the mouse.

Declaration

public void HandleMouseDoubleClick(Control parent, MouseEventArgs e)

Parameters

System.Windows.Forms.Control parent the control hosting the html to set cursor and invalidate

System.Windows.Forms.MouseEventArgs e mouse event args

HandleMouseDown(Control, MouseEventArgs)

Handle mouse down to handle selection.

Declaration

public void HandleMouseDown(Control parent, MouseEventArgs e)

Parameters

System.Windows.Forms.Control parent the control hosting the html to invalidate

System.Windows.Forms.MouseEventArgs e the mouse event args

HandleMouseLeave(Control)

Handle mouse leave to handle hover cursor.

Declaration

public void HandleMouseLeave(Control parent)

Parameters

System.Windows.Forms.Control parent the control hosting the html to set cursor and invalidate

HandleMouseMove(Control, MouseEventArgs)

Handle mouse move to handle hover cursor and text selection.

Declaration

public void HandleMouseMove(Control parent, MouseEventArgs e)

Parameters

System.Windows.Forms.Control parent the control hosting the html to set cursor and invalidate

System.Windows.Forms.MouseEventArgs e the mouse event args

HandleMouseUp(Control, MouseEventArgs)

Handle mouse up to handle selection and link click.

Declaration

public void HandleMouseUp(Control parent, MouseEventArgs e)

Parameters

System.Windows.Forms.Control parent the control hosting the html to invalidate

System.Windows.Forms.MouseEventArgs e the mouse event args

PerformLayout(Graphics)

Measures the bounds of box and children, recursively.

Declaration

public void PerformLayout(Graphics g)

Parameters

System.Drawing.Graphics g Device context to draw

PerformPaint(Graphics)

Render the html using the given device.

Declaration

public void PerformPaint(Graphics g)

Parameters

System.Drawing.Graphics g the device to use to render

SetHtml(String, CssData)

Init with optional document and stylesheet.

Declaration

public void SetHtml(string htmlSource, CssData baseCssData = null)

Parameters

System.String htmlSource the html to init with, init empty if not given

CssData baseCssData optional: the stylesheet to init with, init default if not given

Events

ImageLoad

Raised when an image is about to be loaded by file path or URI.
This event allows to provide the image manually, if not handled the image will be loaded from file or download from URI.

Declaration

public event EventHandler<HtmlImageLoadEventArgs> ImageLoad

Event Type

System.EventHandler<HtmlImageLoadEventArgs>

LinkClicked

Raised when the user clicks on a link in the html.
Allows canceling the execution of the link.

Declaration

public event EventHandler<HtmlLinkClickedEventArgs> LinkClicked

Event Type

System.EventHandler<HtmlLinkClickedEventArgs>

LoadComplete

Raised when the set html document has been fully loaded.
Allows manipulation of the html dom, scroll position, etc.

Declaration

public event EventHandler LoadComplete

Event Type

System.EventHandler

Refresh

Raised when html renderer requires refresh of the control hosting (invalidation and re-layout).

Declaration

public event EventHandler<HtmlRefreshEventArgs> Refresh

Event Type

System.EventHandler<HtmlRefreshEventArgs>

Remarks

There is no guarantee that the event will be raised on the main thread, it can be raised on thread-pool thread.

RenderError

Raised when an error occurred during html rendering.

Declaration

public event EventHandler<HtmlRenderErrorEventArgs> RenderError

Event Type

System.EventHandler<HtmlRenderErrorEventArgs>

Remarks

There is no guarantee that the event will be raised on the main thread, it can be raised on thread-pool thread.

ScrollChange

Raised when Html Renderer request scroll to specific location.
This can occur on document anchor click.

Declaration

public event EventHandler<HtmlScrollEventArgs> ScrollChange

Event Type

System.EventHandler<HtmlScrollEventArgs>

StylesheetLoad

Raised when a stylesheet is about to be loaded by file path or URI by link element.
This event allows to provide the stylesheet manually or provide new source (file or Uri) to load from.
If no alternative data is provided the original source will be used.

Declaration

public event EventHandler<HtmlStylesheetLoadEventArgs> StylesheetLoad

Event Type

System.EventHandler<HtmlStylesheetLoadEventArgs>

Extension Methods

SvgExtentions.Traverse<T>(T, Func<T, IEnumerable<T>>)

SvgExtentions.TraverseDepthFirst<T>(T, Func<T, IEnumerable<T>>)

See Also

TheArtOfDev.HtmlRenderer.WinForms.HtmlContainer.HtmlContainerInt