fix RGBA/BGRA bug, working selection screenshot, code cleanup

src/main.rs

@@ -1,84 +1,151 @@
-use x11::xlib::{XGrabPointer, XCreateFontCursor, XOpenDisplay, Display, XDefaultRootWindow, XAllPlanes, ZPixmap, XGetImage, ButtonMotionMask, ButtonPressMask, ButtonReleaseMask, CurrentTime, GrabModeAsync, GrabSuccess, XNextEvent, XEvent, XPending, ButtonPress, ButtonRelease, XButtonEvent, XGrabKeyboard, KeyPress, XKeyEvent};
+use x11::xlib;
 use std::mem::MaybeUninit;
-use image::RgbaImage;
+use image::{RgbaImage};
 use std::convert::TryInto;
 
 #[derive(Debug)]
 struct Position {
-  origin_x: u32,
+  origin_x: i32,
-  origin_y: u32,
+  origin_y: i32,
   height: u32,
   width: u32,
 }
 
 fn screenshot(pos: &Position) {
-    unsafe {
+  let len: usize = (pos.height as usize)*(pos.width as usize)*4;
-      let display: *mut Display = XOpenDisplay(std::ptr::null());
+  let mut data: Vec<u8> = unsafe {
-      let root_window = XDefaultRootWindow(display);
+    let display: *mut xlib::Display = xlib::XOpenDisplay(std::ptr::null());
+    let root_window = xlib::XDefaultRootWindow(display);
 
-      let ximg = XGetImage(display, root_window, pos.origin_x.try_into().unwrap(), pos.origin_y.try_into().unwrap(), pos.width.try_into().unwrap(), pos.height.try_into().unwrap(), XAllPlanes(), ZPixmap);
+    let ximg = xlib::XGetImage(display,
-      let len = pos.height*pos.width*4;
+                               root_window,
-      let v = Vec::<u8>::from_raw_parts((*ximg).data as *mut _, len.try_into().unwrap(), len.try_into().unwrap());
+                               pos.origin_x,
-      //println!("{:?}", v);
+                               pos.origin_y,
-      let img = RgbaImage::from_raw(pos.width, pos.height, v).unwrap();
+                               pos.width,
+                               pos.height,
+                               xlib::XAllPlanes(),
+                               xlib::ZPixmap);
+    Vec::<u8>::from_raw_parts((*ximg).data as *mut _, len, len)
+  };
   
-      img.save("empty.jpg").unwrap();
+  let mut c = 0;
+
+  while c < len {
+    data.swap(c,c+2);
+    c+=4;
   }
   
+  let img = RgbaImage::from_raw(pos.width, pos.height, data).unwrap();
+  
+  img.save("empty.png").unwrap();
 }
 
 // https://bbs.archlinux.org/viewtopic.php?id=85378
-fn trigger_selection() -> Option<Position> {
+fn select_zone() -> Option<Position> {
 
     unsafe {
-      let display: *mut Display = XOpenDisplay(std::ptr::null());
+      let display: *mut xlib::Display = xlib::XOpenDisplay(std::ptr::null());
-      let root_window = XDefaultRootWindow(display);
+      let root_window = xlib::XDefaultRootWindow(display);
       
-      let c = XCreateFontCursor(display, 130); // XC_tcross = 130
+      let c = xlib::XCreateFontCursor(display, 130); // xlib::XC_tcross = 130
-      let button_mask = ButtonMotionMask as u32 | ButtonPressMask as u32 | ButtonReleaseMask as u32;
 
-      if XGrabPointer(display, root_window, 0, button_mask, GrabModeAsync, GrabModeAsync, root_window, c, CurrentTime) != GrabSuccess {
+      let button_mask = xlib::ButtonMotionMask as u32 | xlib::ButtonPressMask as u32 | xlib::ButtonReleaseMask as u32;
+ 
+      if xlib::XGrabPointer(display, root_window, 0, button_mask, xlib::GrabModeAsync, xlib::GrabModeAsync, root_window, c, xlib::CurrentTime) != xlib::GrabSuccess {
         panic!("could not grab");
       }
 
-      if XGrabKeyboard(display, root_window, 0, GrabModeAsync, GrabModeAsync, CurrentTime) != GrabSuccess {
+      if xlib::XGrabKeyboard(display, root_window, 0, xlib::GrabModeAsync, xlib::GrabModeAsync, xlib::CurrentTime) != xlib::GrabSuccess {
         panic!("could not grab");
       }
 
       let mut pos = Position { origin_x: 0, origin_y: 0, width: 0, height: 0};
 
-      'main: loop {
+      let mut gcv = xlib::XGCValues {
-        while XPending(display) > 0 {
+        foreground: (255<<16),
-          let mut e: MaybeUninit<XEvent> = MaybeUninit::uninit();
+        subwindow_mode: xlib::IncludeInferiors,
-          XNextEvent(display, e.as_mut_ptr());
+        plane_mask: 0,
+        function: xlib::GXxor,
+        background: 0,
+        line_width: 2,
+        line_style: 0,
+        cap_style: 0,
+        join_style: 0,
+        fill_style: 0,
+        fill_rule: 0,
+        arc_mode: 0,
+        tile: 0,
+        stipple: 0,
+        ts_x_origin: 0,
+        ts_y_origin: 0,
+        font: 0,
+        graphics_exposures: 0,
+        clip_x_origin: 0,
+        clip_y_origin: 0,
+        clip_mask: 0,
+        dash_offset: 0,
+        dashes: 0,
+      };
+      let gcv_mask = xlib::GCSubwindowMode | xlib::GCLineWidth | xlib::GCForeground | xlib::GCFunction;
+
+      let mut old_coord = (0,0);
+      let gc = xlib::XCreateGC(display, root_window, gcv_mask.into(), &mut gcv);
+      
+      // https://stackoverflow.com/questions/38996916/x11-draw-overlay-remove-drawings-from-overlay
+      
+      loop {
+        while xlib::XPending(display) > 0 {
+          let mut e: MaybeUninit<xlib::XEvent> = MaybeUninit::uninit();
+          xlib::XNextEvent(display, e.as_mut_ptr());
+
+          let event = e.assume_init();
       
-          let event = unsafe { e.assume_init() };
           match event.type_ {
-            KeyPress => {
+            xlib::MotionNotify => {
-               let event = XKeyEvent::from(event);
+              let event = xlib::XMotionEvent::from(event);
+
+              let width = event.x_root - pos.origin_x;
+              let height = event.y_root - pos.origin_y;
+
+              if height < 0 || width < 0 {
+                return None;
+              }
+              
+              xlib::XDrawRectangle(display, root_window, gc, pos.origin_x, pos.origin_y, old_coord.0, old_coord.1);
+              xlib::XDrawRectangle(display, root_window, gc, pos.origin_x, pos.origin_y, width.try_into().unwrap(), height.try_into().unwrap());
+              
+              old_coord = (width.try_into().unwrap(), height.try_into().unwrap());
+            },
+            xlib::KeyPress => {
+              let event = xlib::XKeyEvent::from(event);
+              
               if event.keycode == 9 { // escape keycode (xev)
                  return None;
               }
             },
-            ButtonPress => {
+            xlib::ButtonPress => {
-               let event = XButtonEvent::from(event);
+              let event = xlib::XButtonEvent::from(event);
-               println!("origin = ({},{})", event.x, event.y);
+              //println!("origin = ({},{})", event.x, event.y);
+              
               pos.origin_x = event.x_root.try_into().unwrap();
               pos.origin_y = event.y_root.try_into().unwrap();
             },
-            ButtonRelease => {
+            xlib::ButtonRelease => {
               // assuming that the upper left corner is the origin
-                let event = XButtonEvent::from(event);
+              let event = xlib::XButtonEvent::from(event);
+
               let x: u32 = event.x_root.try_into().unwrap();
               let y: u32 = event.y_root.try_into().unwrap();
 
-                pos.width = x - pos.origin_x;
+              pos.width = x - pos.origin_x as u32;
-                pos.height = y - pos.origin_y;
+              pos.height = y - pos.origin_y as u32;
               
               if pos.height == 0 || pos.width == 0 {
                 return None
               }
 
+              xlib::XDrawRectangle(display, root_window, gc, pos.origin_x, pos.origin_y, pos.width, pos.height);
+              xlib::XFlush(display);
               return Some(pos);
             }
             _ => { println!("type unknown: {}", event.type_); }
@@ -92,7 +159,7 @@ fn trigger_selection() -> Option<Position> {
 }
 
 fn main() {
-  let s = trigger_selection();
+  let s = select_zone();
   println!("{:?}", s);
   if let Some(select) = s {
     screenshot(&select);