如何使用CoreText在富文本中绘制图像？ （IOS） [英] How to draw images among rich-text with CoreText? (iOS)

问题描述

我可以使用Core Text绘制富文本，问题是将图像与文本一起流动。
（iOS SDK 4.1）

I can draw rich-text with Core Text, the problem is placing images flowing with the text. (iOS SDK 4.1)

我正在尝试绘制某种富文本格式。问题是设计师在文本中放置了许多图标。所以我要绘制的内容是这样的：

I'm try to drawing some kind of rich-text. Problem is designer placed many icons among text. So the text what I have to draw is something like this:

Here is a word <an icon image>, and another words.
The image(<another icon>) should be placed like a glyph.
It's part of text, not an example.

< icon> 是图片。 （这不是代码。只是一个例子。）

<icon> are images. (This is not a code. Just an illustration.)

我可以通过手动布置所有这些来绘制它，但是保持复杂的文本布局行为太难了。所以我找到了一种用Core Text绘制它的方法。

I can draw this by laying out all of them manually, but it's too hard keeping complex text layout behaviors. So I'm finding a way to draw this with Core Text.

推荐答案

我得到了解决方案。

布置非文本内容的关键是 CTRunDelegate 。
核心文本不支持非文本内容，因此您必须为它们创建空格，并在以后绘制或放置它们。

The key of laying out non-text content is CTRunDelegate. Core Text does not support non-text content, so you have to make blank spaces for them, and draw or place them yourself later.

归因于 kCTRunDelegateAttributeName 的 NSAttributedString 的一部分将调用已注册的回调来确定宽度每个字形。这将允许您为每个非文本对象创建空白。

A part of NSAttributedString attributed with kCTRunDelegateAttributeName will call registered callback to determine width of each glyph. This will let you make blank space for each non-text object.

然而，在使用核心文本，使用frame / line / run存储的布局信息将无效。因此，您必须在使用framesetter / typesetter进行布局之后，但在绘制之前绘制/放置非文本内容。

However, after drawing the text with Core Text, the layout information stored with frame/line/run will invalidated. So you have to draw/place non-text contents after layout with framesetter/typesetter, but before drawing.

此链接描述了CTRunDelegate的基本用法：

如何在iPad中使用CTRunDelegate？

This link describes basic usage of CTRunDelegate:
How to use CTRunDelegate in iPad?

Core Text存在问题。最初，CTRunDelegate旨在通过 CTRunDelegateCallbacks.getAscent 和 CTRunDelegateCallbacks.getDescent 支持可变宽度和垂直对齐。但是垂直对齐功能目前不起作用。这可能是一个错误。

There is a problem with Core Text. Originally, CTRunDelegate designed to support variable width and vertical alignment via CTRunDelegateCallbacks.getAscent and CTRunDelegateCallbacks.getDescent. But vertical alignment feature doesn't work currently. This might be a bug.

我在这里描述了这个问题：
使用iOS中的核心文本对齐多个大小的文本垂直中心而不是基线

I described this problem here: Aligning multiple sized text vertical center instead of baseline with Core Text in iOS

如果您有关于此问题的信息，请在链接中查看我的问题。

If you have informations about this problem, please see my question at the link.

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