kernel: Implement basic messageboxes

fox32os.def

@@ -28,6 +28,7 @@ move_window:               jmp [0x00000C24]
 fill_window:               jmp [0x00000C28]
 get_window_overlay_number: jmp [0x00000C2C]
 start_dragging_window:     jmp [0x00000C30]
+new_messagebox:            jmp [0x00000C34]
 
 ; VFS jump table
 open:                      jmp [0x00000D10]

kernel/main.asm

@@ -44,6 +44,7 @@ jump_table:
     data.32 fill_window
     data.32 get_window_overlay_number
     data.32 start_dragging_window
+    data.32 new_messagebox
 
     ; VFS jump table
     org.pad 0x00000510

kernel/window/messagebox.asm

@@ -0,0 +1,116 @@
+; messagebox routines
+
+; create a messagebox in the center of the screen
+; the calling task will not regain control until the user clicks the OK button
+; inputs:
+; r0: pointer to null-terminated first line string
+; r1: pointer to null-terminated second line string
+; r2: pointer to null-terminated third line string
+; r3: X coordinate
+; r4: Y coordinate
+; r5: width in pixels
+; outputs:
+; none
+new_messagebox:
+    push r0
+    push r1
+    push r2
+    push r3
+    push r4
+    push r5
+
+    push r2
+    push r1
+    push r0
+
+    ; save the currently active window offset
+    mov.8 [messagebox_old_active_window_offset], [active_window_offset]
+
+    ; create the window
+    mov r0, messagebox_window_struct
+    mov r1, messagebox_window_title
+    mov r2, r5
+    mov r5, r4
+    mov r4, r3
+    mov r3, 72
+    mov r6, 0
+    mov r7, messagebox_ok_button_widget
+    call new_window
+
+    ; fill the window with white and don't redraw the titlebar
+    mov r0, messagebox_window_struct
+    call get_window_overlay_number
+    mov r1, r0
+    mov r0, 0xFFFFFFFF
+    call fill_overlay
+
+    ; draw the button widget
+    mov r0, messagebox_window_struct
+    call draw_widgets_to_window
+
+    ; draw the strings
+    mov r0, messagebox_window_struct
+    call get_window_overlay_number
+    mov r5, r0
+    pop r0
+    mov r1, 8
+    mov r2, 8
+    mov r3, 0xFF000000
+    mov r4, 0xFFFFFFFF
+    call draw_str_to_overlay
+    pop r0
+    mov r1, 8
+    add r2, 16
+    call draw_str_to_overlay
+    pop r0
+    mov r1, 8
+    add r2, 16
+    call draw_str_to_overlay
+
+messagebox_event_loop:
+    mov r0, messagebox_window_struct
+    call get_next_window_event
+
+    ; was the mouse clicked?
+    cmp r0, EVENT_TYPE_MOUSE_CLICK
+    ifz mov r0, messagebox_window_struct
+    ifz push messagebox_event_loop
+    ifz jmp handle_widget_click
+
+    ; did the user click a button?
+    cmp r0, EVENT_TYPE_BUTTON_CLICK
+    ifz jmp messagebox_ok_clicked
+
+    call yield_task
+    jmp messagebox_event_loop
+
+messagebox_ok_clicked:
+    mov r0, messagebox_window_struct
+    call destroy_window
+
+    ; restore the old active window offset
+    mov.8 [active_window_offset], [messagebox_old_active_window_offset]
+
+    pop r5
+    pop r4
+    pop r3
+    pop r2
+    pop r1
+    pop r0
+    ret
+
+messagebox_window_title: data.str "Messagebox" data.8 0
+messagebox_window_struct: data.fill 0, 36
+messagebox_ok_button_widget:
+    data.32 0                        ; next_ptr
+    data.32 0                        ; id
+    data.32 WIDGET_TYPE_BUTTON       ; type
+    data.32 messagebox_ok_button_str ; text_ptr
+    data.32 0xFFFFFFFF               ; foreground_color
+    data.32 0xFF000000               ; background_color
+    data.16 32                       ; width
+    data.16 0                        ; reserved
+    data.16 8                        ; x_pos
+    data.16 64                       ; y_pos
+messagebox_ok_button_str: data.str "OK" data.8 0
+messagebox_old_active_window_offset: data.8 0

kernel/window/window.asm

@@ -698,4 +698,5 @@ window_list: data.fill 0, 124 ; 31 window structs * 4 bytes each
 
     #include "window/event.asm"
     #include "window/event_manager_task.asm"
+    #include "window/messagebox.asm"
     #include "window/overlay.asm"