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Buffers, language, script and direction
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Creating and destroying buffers
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Adding text to the buffer
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Setting buffer properties
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What about the other scripts?
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Customizing Unicode functions
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The input to Harfbuzz is a series of Unicode characters, stored in a
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buffer. In this chapter, we'll look at how to set up a buffer with
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the text that we want and then customize the properties of the
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buffer.
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Creating and destroying buffers
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As we saw in our initial example, a buffer is created and
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initialized with hb_buffer_create(). This
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produces a new, empty buffer object, instantiated with some
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default values and ready to accept your Unicode strings.
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Harfbuzz manages the memory of objects that it creates (such as
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buffers), so you don't have to. When you have finished working on
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a buffer, you can call hb_buffer_destroy():
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hb_buffer_t *buffer = hb_buffer_create();
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...
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hb_buffer_destroy(buffer);
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This will destroy the object and free its associated memory -
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unless some other part of the program holds a reference to this
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buffer. If you acquire a Harfbuzz buffer from another subsystem
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and want to ensure that it is not garbage collected by someone
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else destroying it, you should increase its reference count:
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void somefunc(hb_buffer_t *buffer) {
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buffer = hb_buffer_reference(buffer);
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...
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And then decrease it once you're done with it:
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hb_buffer_destroy(buffer);
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}
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To throw away all the data in your buffer and start from scratch,
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call hb_buffer_reset(buffer). If you want to
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throw away the string in the buffer but keep the options, you can
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instead call hb_buffer_clear_contents(buffer).
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