func RedrawWindow(W *XWindow, tweetsList []*TweetInfo, mouseClick [2]int) {
var Attribs C.XWindowAttributes
C.XGetWindowAttributes(W.Display, W.Window, &Attribs)
// TODO -- Do this only when resizing?
C.cairo_xlib_surface_set_size(W.Surface, Attribs.width, Attribs.height)
C.cairo_set_source_rgb(W.Cairo, 0.1, 0.1, 0.1)
C.cairo_paint(W.Cairo)
var Rect C.PangoRectangle
yPos := 10.0 + W.Scroll
WindowWidth := Attribs.width
maxTweetWidth := PixelsToPango(float64(WindowWidth - 5*UIPadding - UserImageSize))
for i := 0; i < len(tweetsList); i++ {
t := tweetsList[i]
C.pango_layout_set_width(t.Layout, maxTweetWidth)
C.pango_layout_get_extents(t.Layout, nil, &Rect)
// Get tweet text size
_, ry, _, rh := PangoRectToPixels(&Rect)
// Position and add padding
ry += yPos
if rh < UserImageSize+2*UIPadding-UIPadding {
rh = UserImageSize + 2*UIPadding
} else {
rh += UIPadding
}
// Draw rectangle around tweet
C.cairo_set_source_rgb(W.Cairo, 0.2, 0.2, 0.2)
C.cairo_rectangle(W.Cairo, UIPadding, C.double(ry), C.double(WindowWidth-2*UIPadding), C.double(rh))
C.cairo_fill(W.Cairo)
if mouseClick[0] >= UIPadding && float64(mouseClick[1]) >= ry && float64(mouseClick[1]) <= ry+rh {
fmt.Println("Clicked tweet", t.Text)
}
// Draw user image
userImage := GetCachedImage(W.UserImages, t.UserImage)
if userImage == nil || C.cairo_surface_status(userImage) != C.CAIRO_STATUS_SUCCESS {
userImage = placeholderImage
}
C.cairo_set_source_surface(W.Cairo, userImage, 2*UIPadding, C.double(yPos+UIPadding))
C.cairo_paint(W.Cairo)
// Draw tweet text
C.cairo_move_to(W.Cairo, 63, C.double(yPos+SmallPadding))
C.cairo_set_source_rgb(W.Cairo, 0.95, 0.95, 0.95)
C.pango_cairo_show_layout(W.Cairo, t.Layout)
yPos += 5 + rh
}
}
//export our_area_draw_callback
func our_area_draw_callback(widget *C.GtkWidget, cr *C.cairo_t, data C.gpointer) C.gboolean {
var x0, y0, x1, y1 C.double
var maxwid, maxht C.gint
s := (*sysData)(unsafe.Pointer(data))
// thanks to desrt in irc.gimp.net/#gtk+
// these are in user coordinates, which match what coordinates we want by default, even out of a draw event handler (thanks johncc3, mclasen, and Company in irc.gimp.net/#gtk+)
C.cairo_clip_extents(cr, &x0, &y0, &x1, &y1)
// we do not need to clear the cliprect; GtkDrawingArea did it for us beforehand
cliprect := image.Rect(int(x0), int(y0), int(x1), int(y1))
// the cliprect can actually fall outside the size of the Area; clip it by intersecting the two rectangles
C.gtk_widget_get_size_request(widget, &maxwid, &maxht)
cliprect = image.Rect(0, 0, int(maxwid), int(maxht)).Intersect(cliprect)
if cliprect.Empty() { // no intersection; nothing to paint
return C.FALSE // signals handled without stopping the event chain (thanks to desrt again)
}
i := s.handler.Paint(cliprect)
surface := C.cairo_image_surface_create(
C.CAIRO_FORMAT_ARGB32, // alpha-premultiplied; native byte order
C.int(i.Rect.Dx()),
C.int(i.Rect.Dy()))
if status := C.cairo_surface_status(surface); status != C.CAIRO_STATUS_SUCCESS {
panic(fmt.Errorf("cairo_create_image_surface() failed: %s\n",
C.GoString(C.cairo_status_to_string(status))))
}
// the flush and mark_dirty calls are required; see the cairo docs and https://git.gnome.org/browse/gtk+/tree/gdk/gdkcairo.c#n232 (thanks desrt in irc.gimp.net/#gtk+)
C.cairo_surface_flush(surface)
toARGB(i, uintptr(unsafe.Pointer(C.cairo_image_surface_get_data(surface))),
int(C.cairo_image_surface_get_stride(surface)))
C.cairo_surface_mark_dirty(surface)
C.cairo_set_source_surface(cr,
surface,
0, 0) // origin of the surface
// that just set the brush that cairo uses: we have to actually draw now
// (via https://developer.gnome.org/gtkmm-tutorial/stable/sec-draw-images.html.en)
C.cairo_rectangle(cr, x0, y0, x1, y1) // breaking the nrom here since we have the coordinates as a C double already
C.cairo_fill(cr)
C.cairo_surface_destroy(surface) // free surface
return C.FALSE // signals handled without stopping the event chain (thanks to desrt again)
}
func (self *Surface) SetSourceSurface(surface *Surface, x, y float64) {
C.cairo_set_source_surface(self.context, surface.surface, C.double(x), C.double(y))
}
// SetSourceSurface is a wrapper around cairo_set_source_surface().
func (v *Context) SetSourceSurface(surface *Surface, x, y float64) {
C.cairo_set_source_surface(v.native(), surface.native(), C.double(x),
C.double(y))
}
//SetSourceSurface is a convenience function for creating a pattern
//from a surface and setting it as the source pattern in c
//with SetSource.
//
//The originDisplacement vector gives the user-space coordinates
//at which the surface origin should appear.
//The surface origin is its upper-left corner before any transformation
//has been applied.
//The x and y components of the vector are negated and then set
//as the translation values in the pattern matrix.
//
//Other than the initial pattern matrix, described above, all other
//pattern attributes are set to their default values.
//The resulting pattern can be retrieved by calling Source.
//
//Originally cairo_set_source_surface.
func (c *Context) SetSourceSurface(s Surface, originDisplacement Point) error {
sr := s.XtensionRaw()
x, y := originDisplacement.c()
C.cairo_set_source_surface(c.c, sr, x, y)
return c.Err()
}