diff options
Diffstat (limited to 'examples/shapes/main.go')
| -rw-r--r-- | examples/shapes/main.go | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/examples/shapes/main.go b/examples/shapes/main.go index 0cf7f9c..cfd873c 100644 --- a/examples/shapes/main.go +++ b/examples/shapes/main.go @@ -193,7 +193,11 @@ func main() { // There's also a fill variant for all drawing commands: xproto.PolyFillRectangle(X, draw, red, rectangles2) - // Draw the text: + // Draw the text. Xorg currently knows two ways of specifying text: + // a) the (extended) ASCII encoding using ImageText8(..., []byte) + // b) UTF16 encoding using ImageText16(..., []Char2b) -- Char2b is simply two bytes + // at the bottom of this file, there are two utility functions that help + // convert a go string into an array of Char2b's. xproto.ImageText16(X, byte(len(text)), draw, textCtx, 10, 160, text) case xproto.DestroyNotifyEvent: @@ -207,6 +211,11 @@ func main() { } } +// Char2b is defined as +// Byte1 byte +// Byte2 byte +// and is used as a utf16 character. +// This function takes a string and converts each rune into a char2b. func convertStringToChar2b(s string) []xproto.Char2b { var chars []xproto.Char2b var p []uint16 @@ -216,13 +225,18 @@ func convertStringToChar2b(s string) []xproto.Char2b { if len(p) == 1 { chars = append(chars, convertUint16ToChar2b(p[0])) } else { - chars = append(chars, xproto.Char2b{Byte1: 0, Byte2: 32}) // add a blank instead + // If the utf16 representation is larger than 2 bytes + // we can not use it and insert a blank instead: + chars = append(chars, xproto.Char2b{Byte1: 0, Byte2: 32}) } } return chars } +// convertUint16ToChar2b converts a uint16 (which is basically two bytes) +// into a Char2b by using the higher 8 bits of u as Byte1 +// and the lower 8 bits of u as Byte2. func convertUint16ToChar2b(u uint16) xproto.Char2b { return xproto.Char2b{ Byte1: byte((u & 0xff00) >> 8), |