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DzHTMLText

Delphi and Lazarus HTML Label component

Delphi Supported Versions Platforms Auto Install VCL and FMX Lazarus support CJK line break

ko-fi

What's New

<details> <summary>Click here to view the entire changelog</summary> </details>

Component Description

This visual component allows you to specify a formatted text in a label, using almost the same syntax used in HTML code.

Available Tags

<DIV:{DIV_PARAMS}></DIV> - Div Area
  DIV_PARAMS: (split by ",")
    [x=nnn] --> when defined, div will be floating
    [y=nnn] --> when defined, div will be floating
    [width=size|size#|size-|perc%|full] - when not specified, will be AutoWidth
    [height=size|size#|size-|perc%|full|line] - when not specified, will be AutoHeight
      Width and Height params:
        size = Fixed External Size
        size# = Fixed Internal Size
        size- = Remaining parent div size minus this size (only works when AutoWidth/AutoHeight of parent div is disabled)
        perc% = Percent size of parent div (only works when AutoWidth/AutoHeight of parent div is disabled)
        "full" = Remaining size of current line (only works when AutoWidth/AutoHeight of parent div is disabled)
        "line" = Current line height (only in Height param)
    [maxwidth=nnn] --> Max width when using auto width (when width not specified)
    [margin[_left|_top|_right|_bottom]=nnn] --> Spacing between border line and text
    [thick[_left|_top|_right|_bottom]=nnn] --> Border line size
    [pad[_left|_top|_right|_bottom]=nnn] --> Spacing between outter limit and border line
    [lncolor[_left|_top|_right|_bottom]={COLOR_VALUE}] --> Border line color
    [color={COLOR_VALUE}] --> Color inside the border line
    [outcolor={COLOR_VALUE}] --> Color outside the border line
    [align=left|center|right] --> Horizontal overall alignment
    [valign=top|center|bottom] --> Vertival overall alignment
    [behind] --> When floating, the div will be draw behind the text, otherwise will be draw in the front of the text.
    [holdprops] --> When entering a div, some text properties are reseted. Use "holdprops" param to keep these properties.
      Reseted properties: Offset, Background color, Horizontal and Vertical text alignment, line and paragraph spacing, and Paragraph Indent.

<A[:target]></A> - Link
<B[:off]></B> - Bold
<I[:off]></I> - Italic
<U[:off]></U> - Underline
<S[:off]></S> - Strike out
<FN:abc></FN> - Font Name
<FS:123></FS> - Font Size
<FC:{COLOR_VALUE}></FC> - Font Color
<BC:{COLOR_VALUE}></BC> - Background Color
<H:1..6></H> - Header predefined style - font size (calculated according to component main font size) and bold style
<STYLE:name></STYLE> - Custom style, according to CustomStyles collection property (name must be the same as Custom Style "Ident" property - case insensitive)
<BR[:cont]> - Line Break (Use "cont" parameter to a continous line. If parameter not specified, a new paragraph will be considered)
<NBR> - Prevent new line if used after a line break sequence
<L></L> - Align Left
<C></C> - Align Center
<R></R> - Align Right
<IMG:index> - Image from ImageList where 'index' is image index
<IMGRES:name> - PNG image from Resource where 'name' is the resource name
<UL></UL> - Unordered list
<OL></OL> - Ordered list
<LI></LI> - List item
<SPOILER:name[,exp]></SPOILER> - Spoiler Title (use "exp" param to show spoiler already expanded)
<SDETAIL:name></SDETAIL> - Spoiler Detail
<LS:aaa[,par=bbb]></LS> - Line spacing where 'aaa' is the height in pixels, and 'bbb' is the height when a new paragraph (plus original line space)
<PI:nnn></PI> - Paragraph Indent - left margin of a new paragraph in pixels
<SUP></SUP> - Superscript
<SUB></SUB> - Subscript
<LINE:[width=123|full],[height=456],[color={COLOR_VALUE}],[coloralt={COLOR_VALUE}]> - Horizontal single or dual color line
  "full" option only works when AutoWidth of parent div is disabled
  Default values:
    width = 100
    height = 1
    color = Current font color
    coloralt = No value (specify a color to draw dual color line, otherwise it will draw a single color line)
<VALIGN:top|center|bottom></VALIGN> - Aligning content vertically to the line
<OFFSET:[top=123],[bottom=456]></OFFSET> - Content margin spacing
  Offset margins are memorized if a new offset tag is specifyed without same parameter name
  
OBSOLETE TAGS:
  <T:123> - Tab - left margin offset
  <TF:123> - Tab with continuous lines aligned
  <FLOAT:X,Y[,Width]></FLOAT> - Floating div area
  
----------

* COLOR_VALUE - clColor(VCL)|Color(FMX)|$00GGBBRR|#AARRGGBB|#RRGGBB
* When FMX, all sizes (TPixels) use the "." notation as a decimal separator

The tags notation is case-insensitive, so you can use <B>Text</B> or <b>Text</b>.

Tags must follow the hierarchy as they were opened:

Runtime example

Installing

If you are using Lazarus: go to the Package menu; Open Package File (.lpk); locate LazDzHTMLText.lpk; open the package; Compile it and Install it.

Autoinstall

  1. Download Component Installer from: https://github.com/digao-dalpiaz/CompInstall/releases/latest
  2. Put CompInstall.exe into the component repository sources folder.
  3. Close Delphi IDE and run CompInstall.exe app.

Manual install

  1. Open DzHTMLText.groupproj project in Delphi.
  2. Choose desired platform and ensure Release config are selected in all packages (Design packages must be compiled in Win32 platform).
  3. Right-click at root item in the tree and choose Build All.
  4. Right-click at DzHTMLTextDesign_VCL / DzHTMLTextDesign_FMX and choose Install.
  5. Add Library Path according to the platform in Tools\Options. Example: If you are using Win32, set path = Lib\Win32\Release.

Supports Delphi XE3..Delphi 12

Component Properties

TPixels represents Integer in VCL, or Single in FMX.

AutoBreak: Boolean = When enabled, the component automatically converts Line Break sequence into a new line. If you don't want the line break in a specific sequence, you can use the <NBR> tag after Line Break sequence.

AutoHeight: Boolean = Auto set height of control when Text property changed

AutoWidth: Boolean = Auto set width of control when Text property changed. If you are using AutoWidth, the text never wraps to a new line unless a line break is specified at text or there is a value specified in MaxWidth property.

AutoOpenLink: Boolean = Open links automatically on click over, without set event OnLinkClick.

Borders: TDHBorders = Defines Left, Top, Right and Bottom sub-properties, specifying the text area margins.

Color: TColor = Background color of control. In FMX environment, Null represents transparent background.

CustomStyles: TDHHeaderStyles = Collection of header styles to use with tag <H:ident>, where ident is Ident property of a header style in collection list.

Font: TFont = Determines the base font. When no tag is specified on text, this base font is used.

Images: TCustomImageList = When using <img> tag, you should set this property to specify the ImageList where the images are stored. In FMX environment, this property is only available using Delphi XE8 or higher.

LineCount: Integer = Returns the total lines of text, according to the bounds of control. This property is read-only.

Lines: TStrings = The text you want to show at label control. You can use <BR> tag to break lines. The default Line Break sequence breaks lines either when AutoBreak property is enabled.

LineSpacing: TPixels = Specify the default line spacing in overall text. You can use <LS> tag to determine line spacing at specific lines.

LineHorzAlign: TDHHorzAlign (haLeft, haCenter, haRight) = Allows you to specify the horizontal alignment of each element in the line. Default is haLeft.

LineVertAlign: TDHVertAlign (vaTop, vaCenter, vaBottom) = Allows you to specify the vertical alignment of each element in the line. This property only take effects when the elements have different heights at same line. Default is vaTop.

ListLevelPadding: TPixels = Determines the width of each list level in pixels, when using HTML list tags.

MaxWidth: TPixels = Specify the maximum width of text, when using AutoWidth property.

Offset: TDHOffset = Sets Top and Bottom offset (spacing in Pixels) for each line. When using <offset> tag, it will replace this setting, according to the specified attribute (top and/or bottom).

OverallHorzAlign: TDHHorzAlign (haLeft, haCenter, haRight) = Determines overall text horizontal alignment. This property only take effects if AutoWidth is false.

OverallVertAlign: TDHVertAlign (vaTop, vaCenter, vaBottom) = Determines overall text vertical alignment. This property only take effects if AutoHeight is false.

ParagraphCount: Integer = Returns the total paragraphs of text. This property is read-only.

ParagraphIndent: TPixels = Default left margin of a new paragraph.

ParagraphSpacing: TPixels = Specify the default paragraph spacing in overall text. The paragraph spacing is added to original line spacing. You can use <LS> tag to determine paragraph spacing at specific lines.

StyleLinkNormal: TDHStyleLinkProp = Properties to format a link when is not selected by mouse.

StyleLinkHover: TDHStyleLinkProp = Properties to format a link when is selected by mouse.

SyntaxErrors: TDHSyntaxErrorList (public) = List of syntax errors. Right click on component and choose "Show Syntax Errors" at design time to show syntax errors. When any syntax error, at design time the border of the component will be draw with red color.

Text: string (public) = This property is a shortcut to Lines property. At run-time, you can read and write this property directly, but the component will store the text at Lines property.

TextHeight: TPixels = Returns the total text height. This property is read-only.

TextWidth: TPixels = Returns the total text width. This property is read-only.

Transparent: Boolean (only in VCL) = Enables component transparency. Warning: When using with links, it will cause flickering when redrawing component.

Events

procedure OnLinkEnter(Sender: TObject; Link: TDHBaseLink);

This event is fired when the mouse enters a link area

procedure OnLinkLeave(Sender: TObject; Link: TDHBaseLink);

This event is fired when the mouse leaves a link area

procedure OnLinkClick(Sender: TObject; Link: TDHBaseLink; var Handled: Boolean);

This event is fired when a link is left-clicked by the mouse. You can use Handled var to by-pass the AutoOpenLink property (the handled value is False at method start).

procedure OnLinkRightClick(Sender: TObject; Link: TDHBaseLink; var Handled: Boolean);

This event is fired when a link is right-clicked by the mouse. You can use Handled var to by-pass the AutoOpenLink property (the handled value is False at method start).

procedure OnRetrieveImgRes(Sender: TObject; const ResourceName: string; Picture: TAnyPicture; var Handled: Boolean);

If you are using <imgres> tag, this event will fire on every image tag, allowing you to manually load a image from anywhere, in any image format, assigning it to Picture object. Be sure to set Handled := True when you manually load an image. Not using this event causes the component to automatically load the image from application resources by name, and must be in PNG format when using VCL environment. In FMX environment you can use any image format supported by Delphi.

Example:

procedure TForm1.DzHTMLText1RetrieveImgRes(Sender: TObject; const ResourceName: string;
  Picture: TAnyPicture; var Handled: Boolean);
var JPG: TJpegImage;
begin
  if ResourceName='TEST' then
  begin
    JPG := TJpegImage.Create;
    try
      JPG.LoadFromFile('C:\Test.jpg');
      Picture.Assign(JPG);
    finally
      JPG.Free;
    end;

    Handled := True; 
  end;
end;

Procedures/Functions

function IsLinkHover: Boolean;

This function returns true when the mouse is over a link

function SelectedLink: TDHBaseLink;

This function returns the object of the selected link. A link is selected when the mouse is over it. If there is no link selected, this property is nil.

procedure Rebuild;

This method rebuilds all internal text elements to get component ready to paint. Call this method if you want to get some calculated property, like TextWidth and TextHeight. Otherwise, you don't need to call this procedure directly.

procedure BeginUpdate;

Increments internal update semaphore, so while reference counting is bigger than zero, the component will not repaint automatically when the properties are changed, like changing Text or Font property.

procedure EndUpdate(ForceRepaint: Boolean = True);

Decrements internal update semaphore, so when reference counting is zero, if ForceRepaint parameter is True, then the component will repaint the HTML Text.

BeginUpdate/EndUpdate example:

DzHTMLText1.BeginUpdate;
try
  DzHTMLText1.Text := 'Text <b>test</b> 1234';
  DzHTMLText1.Font.Color := clRed;
  DzHTMLText1.Font.Size := 20;
finally
  DzHTMLText1.EndUpdate;
end;

Do not use Lines.BeginUpdate/Lines.EndUpdate. These methods are not controlled by the component.

Link Reference Tag

There are two ways to use link tag:

  1. Declaring internal link and the text do display:

    <a:www.google.com>Open Google Search</a>

    This will display: Open Google Search

  2. Just using the display text:

    <a>www.google.com</a>

    This will display: www.google.com

You can use any text as internal link code. Then you can handle this code at link events, reading Link parameter.

Do not use link tags (<a>, <spoiler>, <sdetail>) inside a <a> tag!

Spoiler Tag

This tag allows you to create a link and a detail div, where the detail is automatically expanded or collapsed when the mouse clicks on the link.

To create the spoiler link: <spoiler:name>This is the spoiler link text</spoiler>

To create the detail div: <sdetail:name>This is the detail div that will be expanded when the spoiler link is clicked.</sdetail>

The spoiler name is case insensitive.

You can handle spoiler link at link events. It's possible to bypass expand/collapse behavior using Handled property.

You can use another spoilers inside a spoiler detail div.

It's allowed to create multiple links pointing to a single detail div, and it's allowed to create a single link pointing to multiple detail divs.

Do not use link tags (<a>, <spoiler>, <sdetail>) inside a <spoiler> tag!

Link object

TDHBaseLink has two child classes possible:

Properties:

Link events

You can retrieve this object using OnLinkClick / OnLinkRightClick / OnLinkEnter / OnLinkLeave events. Also you can call GetSelectedLink or reading LinkRefs and Spoilers lists.

Image Tag

You can use the tags:

Example:

App Resources Dialog

In this example, the image tag should be <imgres:test>

Div Tag

Div Example

Syntax of the image above:

<div:
margin=40,
thick=5,
pad=20,
lncolor=clGray,
color=clWhite,
outcolor=clLime
><bc:clYellow>Some text inside a div</bc></div>

The component is based in Div areas. This mean the main area of component is a Div, and you can insert sub divs, and another divs inside divs, and so on. The div tag allows you to work with alignment, colors, borders, margin, and you can even make a table using multiple divs.

The div tag may be floating, using specific X and Y position, or docked to the current text, when not specifying any position.

Please, refer to all possible parameters in Available tags.

Tab Tag

There are two tab tags you can use:

Literal tag character

If you want to display literal special characters in the text, just type the HTML code:

There are two class functions to deal with HTML characters:

class function EscapeTextToHTML(const aText: string): string;
class function UnescapeHTMLToText(const aHTML: string): string;

As this component is not a complete HTML language debugger, there is no need to escape the other special characters. Therefore, for characters such as accentuation, for example, or other signs, you must use them normally.

Chinese/Japanese/Korean line break

If you have component width smaller than your text, then it will break to a new line according to some specific chars. These chars are: (space), \ and /. The bars are considered as word break because if you type some path, for example, then should be a way to split this path into a new line if it was too big.

When you type Chinese, Japanese or Korean characters, this behavior is quite different. In this case, the component will break lines considering any char as a complete word.

Auto Scaling

VCL (Delphi and Lazarus)

All measurements will be calculated based on the Design DPI (always 96 pixels per inch), and applied to the current Monitor DPI. Example: if you specified a tab width as 60 pixels, at 96 DPI, when displaying the text on a 120 DPI monitor, the tab width will be larger (75 pixels).

For automatic scaling by DPI to work correctly, it is necessary to use Windows 8.1 or higher, and Delphi 10 or higher, or Lazarus. If using Delphi previous version, the scaling will be disabled. If using Windows previous version, the scaling will be based on the default monitor DPI, and not on application current monitor.

FMX

In FMX environment, auto scaling is controled by Fire Monkey framework, automatically scaling the entire form layout and its components.

Color Notation

When using tags like <fc:color> or <bc:color>, you can specify these color notation options:

You can specify VCL notation when using FMX component, or even using FMX notation when using VCL component. The same for HTML notation.

Formatted Message Dialog Component

Please, take a look at my Message Dialogs Component that uses this HTML Component to display formatted messages. The component will make much more easy to manage your application messages.

https://github.com/digao-dalpiaz/Dam

Message Dialog Example:

Dam Example

Donate

This project has been developed by several years, and I am trying to continuously updating it. To do that, I need to stop other projects, to make time.

If you like this work and it's useful to you, consider to contribute, so I can spend more time to enhance the code and functionalities.

Thank you very much. :grin: