如何在开罗重设当前点? [英] How to reset the current point in cairo?
问题描述
从cairo文档中，我可以看到一些功能，例如文本toy-API cairo_show_text()需要设置当前点.我们可以使用 cairo_move_to()设置当前点，然后调用 cairo_show_text()，它将光栅化所需位置的文本.
From cairo documentation, I can see that some functions, for instance the Text toy-API cairo_show_text() needs a current point to be set.
We can set the current point with cairo_move_to(), and then calling cairo_show_text() it will rasterize the text in the desired location.
顺便说一句，这引起了一个错误，因为在光栅化文本之后，我正在笔触路径，该路径(通过最初调用 cairo_move_to()来设置文本的当前点)具有错误的点
Btw, this caused a bug, because after rasterizing text, I was stroking a path, which (with that initial call to cairo_move_to() to set the current point for the text) had wrong points.
我通过在调用 cairo_show_text()之后立即调用 cairo_stroke()解决了该错误，并且似乎可以正常工作，因为它重置了当前点.
I solved this bug by calling cairo_stroke() immediately after calling cairo_show_text(), and it seems to work, since it resets the current point.
似乎调用 cairo_close_path()而不是 cairo_stroke()并没有帮助.它没有重置当前点.我认为这很奇怪.为什么?
It seems that calling cairo_close_path() instead of cairo_stroke() hasn't been helpful. It didn't reset the current point. And I think this is quite strange. Why?
我的最后一个问题是:是否有适当的方法来重置当前点?我认为应该有.
My final question is: is there a proper way to reset the current point? I think there should be.
推荐答案
来自 cairo_new_path()
cairo_new_path () 清除当前路径.通话之后，将没有路径，也没有当前点. Clears the current path. After this call there will be no path and no current point. 出于完整性考虑:还有一个功能不能清除当前路径: For completeness: There is also this function which does not clear the current path: 来自 https://www.cairographics.org/manual/cairo-Paths.html#cairo-new-sub-path cairo_new_sub_path() cairo_new_sub_path () 开始一个新的子路径.请注意，现有路径不会受到影响.通话后将没有当前点. Begin a new sub-path. Note that the existing path is not affected. After this call there will be no current point. 在许多情况下，由于新的子路径通常以cairo_move_to()开始，因此不需要此调用. In many cases, this call is not needed since new sub-paths are frequently started with cairo_move_to(). 使用 A call to 这篇关于如何在开罗重设当前点?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
cairo_arc()调用之一开始新的子路径时，对 cairo_new_sub_path()的调用特别有用.这使事情变得容易，因为不再需要为调用 cairo_move_to()的调用手动计算弧的初始坐标.cairo_new_sub_path() is particularly useful when beginning a new sub-path with one of the cairo_arc() calls. This makes things easier as it is no longer necessary to manually compute the arc's initial coordinates for a call to cairo_move_to().
