func (le *LineEdit) initCharWidth() {
font := le.Font()
if font == le.charWidthFont {
return
}
le.charWidthFont = font
le.charWidth = 8
hdc := win.GetDC(le.hWnd)
if hdc == 0 {
newError("GetDC failed")
return
}
defer win.ReleaseDC(le.hWnd, hdc)
defer win.SelectObject(hdc, win.SelectObject(hdc, win.HGDIOBJ(font.handleForDPI(0))))
buf := []uint16{'M'}
var s win.SIZE
if !win.GetTextExtentPoint32(hdc, &buf[0], int32(len(buf)), &s) {
newError("GetTextExtentPoint32 failed")
return
}
le.charWidth = int(s.CX)
}
func (wb *WindowBase) dialogBaseUnits() Size {
// The window may use a font different from that in WindowBase,
// like e.g. NumberEdit does, so we try to use the right one.
window := windowFromHandle(wb.hWnd)
hdc := win.GetDC(wb.hWnd)
defer win.ReleaseDC(wb.hWnd, hdc)
hFont := window.Font().handleForDPI(0)
hFontOld := win.SelectObject(hdc, win.HGDIOBJ(hFont))
defer win.SelectObject(hdc, win.HGDIOBJ(hFontOld))
var tm win.TEXTMETRIC
if !win.GetTextMetrics(hdc, &tm) {
newError("GetTextMetrics failed")
}
var size win.SIZE
if !win.GetTextExtentPoint32(
hdc,
dialogBaseUnitsUTF16StringPtr,
52,
&size) {
newError("GetTextExtentPoint32 failed")
}
return Size{int((size.CX/26 + 1) / 2), int(tm.TmHeight)}
}
func (wb *WindowBase) calculateTextSizeImpl(text string) Size {
hdc := win.GetDC(wb.hWnd)
if hdc == 0 {
newError("GetDC failed")
return Size{}
}
defer win.ReleaseDC(wb.hWnd, hdc)
hFontOld := win.SelectObject(hdc, win.HGDIOBJ(wb.window.Font().handleForDPI(0)))
defer win.SelectObject(hdc, hFontOld)
var size Size
lines := strings.Split(text, "\n")
for _, line := range lines {
var s win.SIZE
str := syscall.StringToUTF16(strings.TrimRight(line, "\r "))
if !win.GetTextExtentPoint32(hdc, &str[0], int32(len(str)-1), &s) {
newError("GetTextExtentPoint32 failed")
return Size{}
}
size.Width = maxi(size.Width, int(s.CX))
size.Height += int(s.CY)
}
return size
}
func (cb *ComboBox) calculateMaxItemTextWidth() int {
hdc := win.GetDC(cb.hWnd)
if hdc == 0 {
newError("GetDC failed")
return -1
}
defer win.ReleaseDC(cb.hWnd, hdc)
hFontOld := win.SelectObject(hdc, win.HGDIOBJ(cb.Font().handleForDPI(0)))
defer win.SelectObject(hdc, hFontOld)
var maxWidth int
count := cb.model.ItemCount()
for i := 0; i < count; i++ {
var s win.SIZE
str := syscall.StringToUTF16(cb.itemString(i))
if !win.GetTextExtentPoint32(hdc, &str[0], int32(len(str)-1), &s) {
newError("GetTextExtentPoint32 failed")
return -1
}
maxWidth = maxi(maxWidth, int(s.CX))
}
return maxWidth
}
func (c *Canvas) withGdiObj(handle win.HGDIOBJ, f func() error) error {
oldHandle := win.SelectObject(c.hdc, handle)
if oldHandle == 0 {
return newError("SelectObject failed")
}
defer win.SelectObject(c.hdc, oldHandle)
return f()
}
func (bmp *Bitmap) withSelectedIntoMemDC(f func(hdcMem win.HDC) error) error {
return withCompatibleDC(func(hdcMem win.HDC) error {
hBmpOld := win.SelectObject(hdcMem, win.HGDIOBJ(bmp.hBmp))
if hBmpOld == 0 {
return newError("SelectObject failed")
}
defer win.SelectObject(hdcMem, hBmpOld)
return f(hdcMem)
})
}
func (c *Canvas) MeasureText(text string, font *Font, bounds Rectangle, format DrawTextFormat) (boundsMeasured Rectangle, runesFitted int, err error) {
// HACK: We don't want to actually draw on the Canvas here, but if we use
// the DT_CALCRECT flag to avoid drawing, DRAWTEXTPARAMc.UiLengthDrawn will
// not contain a useful value. To work around this, we create an in-memory
// metafile and draw into that instead.
if c.measureTextMetafile == nil {
c.measureTextMetafile, err = NewMetafile(c)
if err != nil {
return
}
}
hFont := win.HGDIOBJ(font.handleForDPI(c.dpiy))
oldHandle := win.SelectObject(c.measureTextMetafile.hdc, hFont)
if oldHandle == 0 {
err = newError("SelectObject failed")
return
}
defer win.SelectObject(c.measureTextMetafile.hdc, oldHandle)
rect := &win.RECT{
int32(bounds.X),
int32(bounds.Y),
int32(bounds.X + bounds.Width),
int32(bounds.Y + bounds.Height),
}
var params win.DRAWTEXTPARAMS
params.CbSize = uint32(unsafe.Sizeof(params))
strPtr := syscall.StringToUTF16Ptr(text)
dtfmt := uint32(format) | win.DT_EDITCONTROL | win.DT_WORDBREAK
height := win.DrawTextEx(
c.measureTextMetafile.hdc, strPtr, -1, rect, dtfmt, ¶ms)
if height == 0 {
err = newError("DrawTextEx failed")
return
}
boundsMeasured = Rectangle{
int(rect.Left),
int(rect.Top),
int(rect.Right - rect.Left),
int(height),
}
runesFitted = int(params.UiLengthDrawn)
return
}
func NewCanvasFromImage(image Image) (*Canvas, error) {
switch img := image.(type) {
case *Bitmap:
hdc := win.CreateCompatibleDC(0)
if hdc == 0 {
return nil, newError("CreateCompatibleDC failed")
}
succeeded := false
defer func() {
if !succeeded {
win.DeleteDC(hdc)
}
}()
if win.SelectObject(hdc, win.HGDIOBJ(img.hBmp)) == 0 {
return nil, newError("SelectObject failed")
}
succeeded = true
return (&Canvas{hdc: hdc}).init()
case *Metafile:
c, err := newCanvasFromHDC(img.hdc)
if err != nil {
return nil, err
}
c.recordingMetafile = img
return c, nil
}
return nil, newError("unsupported image type")
}