RichText improvements

[summerinsects]

This is a PR to improve RichText.

• Automatically customize ContentSize. Related: Automatically customize ContentSize for RichText.  #12806 formarRenderers in RichText doesn’t update container size #12145 关于RichText的使用问题 #15054

There is a feedback that can not get the real height of a richtext from many forums.
I modify _customSize.height in function RichText::formatRenderers to make content size equals to real size.

• refactor split algorithm with StringUtils::StringUTF8.

  • It is a waste of performance to invokes Helper::getSubStringOfUTF8String several times with same string. StringUtils::StringUTF8 convers string only once.
  • on the other hand, splits StringUtils::StringUTF8 is easier than Helper::getSubStringOfUTF8String. Related: The first character is disappeared at the head of a new line in UIRichTxt #18323
  • add a rough estimate in function getNextWordPos to make it runs faster.

• handle ‘\n’ for new line, and support continuous ‘\n’. Related: UIRichText does not handle well "\n" #14188

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改进RichText

• 自动修正ContentSize，以获得真实高度 Automatically customize ContentSize for RichText.  #12806 formarRenderers in RichText doesn’t update container size #12145 关于RichText的使用问题 #15054

许多论坛反馈RichText无法获取真实高度。我在函数RichText::formatRenderers里面修改了_customSize.height，使得content size等于真实尺寸。

• 用StringUtils::StringUTF8重构了字符串切割算法

  • 对同一段文本重复调用Helper::getSubStringOfUTF8String比较浪费性能。而StringUtils::StringUTF只转换一次。
  • 另一方面，切割StringUtils::StringUTF8比用Helper::getSubStringOfUTF8String切割要容易得多，且不容易出错。The first character is disappeared at the head of a new line in UIRichTxt #18323
  • 在函数getNextWordPos里面增加了估算长度，使之执行得更快。

• 对文本中的\n处理为换行。并支持连续的\n UIRichText does not handle well "\n" #14188

[minggo]

if idx == str.length(), then it may have problem.

[summerinsects]

Yes, it will be out of bounds. I will add an if condition

[minggo]

if textRendererWidth == originalLeftSpaceWidth, then should return newidx instead of idx

[summerinsects]

Yes. I will add an if condition

[minggo]

why need to skip spaces?

[summerinsects]

In original code, it skips one space.
But I think skipping all spaces may be better.

eg(_ instead of space): "abcd________________123"
suppose it is splitted after letter 'd'
Should it desplay like

abcd
123

or

abcd
________________123
? please give me some advice

[minggo]

I have not idea. How it been displayed on Android/iOS UI element? I think can have the same behavior as them.

[summerinsects]

I test it with iOS's webview. It trims the spaces. see below

[minggo]

K, thanks.

[minggo]

why height compare with font size?

[summerinsects]

This is for continuous new lines.
eg："abc\n\n123" should display like this:
abc

123

[minggo]

why height vector record font size?

[summerinsects]

This is also for continuous new lines.
eg："abc\n\n123" should display like this:
abc

123

[minggo]

may be should use another name for the member variable, the name is _defaultHeights , but the element value is font size, it is hard to understand.

[summerinsects]

How about _emptyLineHeights

[minggo]

I don't quite understand why height is equal to font size. When i reviewed the codes, it seems font size is used as height.

[summerinsects]

• there is a RichText with fontSize 20 contains RichElementText(string="abc\n\n123", fontSize=10).
  Then it will display like this:

abc

123

Now, the gap between two lines should be equal to RichElementText's fontSize 10

• In another case, there is a RichText with fontSize 20 contains RichElementText("abc"), RichElementNewLine, RichElementNewLine, RichElementText("123").
  Then it will display like this:

abc

123

Now, the gap between two lines should be equal to RichText's fontSize 20

[summerinsects]

I test it with iOS's webview. It trims the spaces.

[minggo]

if originalLeftSpaceWidth == textRendererWidth, then it should return leftLength

[summerinsects]

OK

[minggo]

Why use font size for height? And when row will be empty?

[summerinsects]

Consider the following two cases：

• a RichText with fontSize 20 contains RichElementText(string="abc\n\n123", fontSize=10).
  Then it will display like this:

abc

123

Now, the gap between two lines should be equal to RichElementText's fontSize 10

• a RichText with fontSize 20 contains RichElementText("abc"), RichElementNewLine, RichElementNewLine, RichElementText("123").
  Then it will display like this:

abc

123

Now, the gap between two lines should be equal to RichText's fontSize 20

In both of two cases, row.empty() == true. because of RichText::addNewLine(), the code _elementRenders.emplace_back();

[minggo]

Why not just use vertical space instead of font size? Use font size as line height is strange.

[summerinsects]

vertical space is not same as font size.please see below

[minggo]

sounds reasonable

[minggo]

When element render will be empty?

[summerinsects]

This is the case of end with some new lines, for example, the last element of a RichText is RichElementNewLine, or RichElementText with some \n's.
RichText::addNewLine() will be invoked, but no renders in the vector.

[minggo]

Why remove them? May be it is the expected effect, use some new line at the end to make some space at the end of content.

[summerinsects]

At first, I think new lines at end of RichText is meaningless.
Maybe we can add a method to decide whether trim or not, how about it?

[minggo]

I think it may make things complex. If they don't want the effect, then why add these new lines explicitly?

[summerinsects]

OK. I see. I will delete these codes

[summerinsects]

In my opinion

[summerinsects]

@minggo
I get inspiration from class Labels source code, which is

const Size& Label::getContentSize() const
{
    if (_systemFontDirty || _contentDirty)
    {
        const_cast<Label*>(this)->updateContent();
    }
    return _contentSize;
}

Rect Label::getBoundingBox() const
{
    const_cast<Label*>(this)->getContentSize();

    return Node::getBoundingBox();
}

It means that when invoke getContentSize with a dirty content, it should update first.

Are these codes necessary similarly?

const Size& RichText::getContentSize() const
{
    if (_formatTextDirty)
    {
        const_cast<RichText*>(this)->formatText();
    }
    return Widget::getContentSize();
}

Rect RichText::getBoundingBox() const
{
    if (_formatTextDirty)
    {
        const_cast<RichText*>(this)->formatText();
    }
    return Widget::getBoundingBox();
}

[minggo]

From the logic it seems it is needed, but i am not sure. Do you meet any problem?

[summerinsects]

I did not notice this problem.
In my code, I always invoked formatText explicitly before getContentSize
I am not sure whether overriding these functions will cause side effects

[minggo]

I am not sure too, since some call back is invoked from UIWidget. So let's keep as it is and fix them when meet issue.

[summerinsects]

OK

[rh101]

Guys, introducing the trimming spaces on the right side of a text element makes no sense. It should not trim any space, since a RichText is made out of several elements, and spaces on the right side of text elements are used to literally put space between those elements.

For example, say you have this UIRichText made up of 3 elements, text, image, and another text:

text[space]Image[space]text

which should be rendered as:

text image text

yet it appears as:

textimagetext

If for some reason you need it to trim right side spaces, then at least give us the option to turn that functionality on or off by some kind of flag bit (such as RichElementText::TRIM_RIGHT_SPACE etc).