// GetFormat searches SetupInfo for a Format matching the depth provided.
func GetFormat(X *xgbutil.XUtil, depth byte) *xproto.Format {
for _, pixForm := range X.Setup().PixmapFormats {
if pixForm.Depth == depth {
return &pixForm
}
}
return nil
}
// checkCompatibility reads info in the X setup info struct and emits
// messages to stderr if they don't correspond to values that xgraphics
// supports.
// The idea is that in the future, we'll support more values.
// The real reason for checkCompatibility is to make debugging easier. Without
// it, if the values weren't what we'd expect, we'd see garbled images in the
// best case, and probably BadLength errors in the worst case.
func checkCompatibility(X *xgbutil.XUtil) {
s := X.Setup()
scrn := X.Screen()
failed := false
if s.ImageByteOrder != xproto.ImageOrderLSBFirst {
log.Printf("Your X server uses MSB image byte order. Unfortunately, " +
"xgraphics currently requires LSB image byte order. You may see " +
"weird things. Please report this.")
failed = true
}
if s.BitmapFormatBitOrder != xproto.ImageOrderLSBFirst {
log.Printf("Your X server uses MSB bitmap bit order. Unfortunately, " +
"xgraphics currently requires LSB bitmap bit order. If you " +
"aren't using X bitmaps, you should be able to proceed normally. " +
"Please report this.")
failed = true
}
if s.BitmapFormatScanlineUnit != 32 {
log.Printf("xgraphics expects that the scanline unit is set to 32, "+
"but your X server has it set to '%d'. "+
"Namely, xgraphics hasn't been tested on other values. Things "+
"may still work. Particularly, if you aren't using X bitmaps, "+
"you should be completely unaffected. Please report this.",
s.BitmapFormatScanlineUnit)
failed = true
}
if scrn.RootDepth != 24 {
log.Printf("xgraphics expects that the root window has a depth of 24, "+
"but yours has depth '%d'. Its possible things will still work "+
"if your value is 32, but will be unlikely to work with values "+
"less than 24. Please report this.", scrn.RootDepth)
failed = true
}
// Look for the default format for pixmaps and make sure bits per pixel
// is 32.
format := xgraphics.GetFormat(X, scrn.RootDepth)
if format.BitsPerPixel != 32 {
log.Printf("xgraphics expects that the bits per pixel for the root "+
"window depth is 32. On your system, the root depth is %d and "+
"the bits per pixel is %d. Things will most certainly not work. "+
"Please report this.",
scrn.RootDepth, format.BitsPerPixel)
failed = true
}
// Give instructions on reporting the issue.
if failed {
log.Printf("Please report the aforementioned error message(s) at " +
"https://github.com/BurntSushi/xgbutil. Please also include the " +
"entire output of the `xdpyinfo` command in your report. Thanks!")
} else {
log.Printf("No compatibility issues detected.")
}
}
// minMaxKeycodeGet a simple accessor to the X setup info to return the
// minimum and maximum keycodes. They are typically 8 and 255, respectively.
func minMaxKeycodeGet(xu *xgbutil.XUtil) (xproto.Keycode, xproto.Keycode) {
return xu.Setup().MinKeycode, xu.Setup().MaxKeycode
}
// readDrawableData uses Format information to read data from an X pixmap
// into an xgraphics.Image.
// readPixmapData does not take into account all information possible to read
// X pixmaps and bitmaps. Of particular note is bit order/byte order.
func readDrawableData(X *xgbutil.XUtil, ximg *Image, did xproto.Drawable,
imgData *xproto.GetImageReply, width, height int) error {
format := GetFormat(X, imgData.Depth)
if format == nil {
return fmt.Errorf("Could not find valid format for pixmap %d "+
"with depth %d", did, imgData.Depth)
}
switch format.Depth {
case 1: // We read bitmaps in as alpha masks.
if format.BitsPerPixel != 1 {
return fmt.Errorf("The image returned for pixmap id %d with "+
"depth %d has an unsupported value for bits-per-pixel: %d",
did, format.Depth, format.BitsPerPixel)
}
// Calculate the padded width of our image data.
pad := int(X.Setup().BitmapFormatScanlinePad)
paddedWidth := width
if width%pad != 0 {
paddedWidth = width + pad - (width % pad)
}
// Process one scanline at a time. Each 'y' represents a
// single scanline.
for y := 0; y < height; y++ {
// Each scanline has length 'width' padded to
// BitmapFormatScanlinePad, which is found in the X setup info.
// 'i' is the index to the starting byte of the yth scanline.
i := y * paddedWidth / 8
for x := 0; x < width; x++ {
b := imgData.Data[i+x/8] >> uint(x%8)
if b&1 > 0 { // opaque
ximg.Set(x, y, BGRA{0x0, 0x0, 0x0, 0xff})
} else { // transparent
ximg.Set(x, y, BGRA{0xff, 0xff, 0xff, 0x0})
}
}
}
case 24:
if format.BitsPerPixel != 24 && format.BitsPerPixel != 32 {
return fmt.Errorf("The image returned for pixmap id %d has "+
"an unsupported value for bits-per-pixel: %d",
did, format.BitsPerPixel)
}
bytesPer := int(format.BitsPerPixel) / 8
var i int
ximg.For(func(x, y int) BGRA {
i = y*width*bytesPer + x*bytesPer
return BGRA{
B: imgData.Data[i],
G: imgData.Data[i+1],
R: imgData.Data[i+2],
A: 0xff,
}
})
default:
return fmt.Errorf("The image returned for pixmap id %d has an "+
"unsupported value for depth: %d", did, format.Depth)
}
return nil
}
