Draw image/text with current transformation appied

[wsw0108]

No description provided.

[fogleman]

The rotated image looks good, but the rotated text looks very aliased. Can it be improved?

[fogleman]

@wsw0108 See my comment above? :)

[wsw0108]

@fogleman oh, I almost forgot this.

I think this should be done by get the vector path of each glyph of the input text, then draw the vector path instead of image.

For now, package golang.org/x/image/font only provide method that get image of glyph. Although package github.com/golang/freetype can be used to get vector path of glyph, it can only process truetype font.