From bb0e67a308922fc1a1a6972b00fcc37909a028ce Mon Sep 17 00:00:00 2001
From: Kartik Agaram <vc@akkartik.com>
Date: Tue, 12 Jan 2021 00:20:22 -0800
Subject: 7501 - baremetal: draw text within a rectangle

---
 baremetal/501draw-text.mu | 51 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

(limited to 'baremetal/501draw-text.mu')

diff --git a/baremetal/501draw-text.mu b/baremetal/501draw-text.mu
index f19536ca..af165e78 100644
--- a/baremetal/501draw-text.mu
+++ b/baremetal/501draw-text.mu
@@ -34,3 +34,54 @@ fn draw-text-rightward screen: (addr screen), text: (addr array byte), x: int, x
   }
   return xcurr
 }
+
+# draw text from (x, y) to (xmax, ymax), wrapping as necessary
+# return the next (x, y) coordinate in raster order where drawing stopped
+# if there isn't enough space, return 0 without modifying the screen
+fn draw-text-rightward-wrapped screen: (addr screen), text: (addr array byte), x: int, y: int, xmax: int, ymax: int, color: int -> _/eax: int, _/ecx: int {
+  var stream-storage: (stream byte 0x100)
+  var stream/esi: (addr stream byte) <- address stream-storage
+  write stream, text
+  # check if we have enough space
+  var xcurr/edx: int <- copy x
+  var ycurr/ecx: int <- copy y
+  {
+    compare ycurr, ymax
+    break-if->=
+    var g/eax: grapheme <- read-grapheme stream
+    compare g, 0xffffffff  # end-of-file
+    break-if-=
+    xcurr <- add 8  # font-width
+    compare xcurr, xmax
+    {
+      break-if-<
+      xcurr <- copy x
+      ycurr <- add 0x10  # font-height
+    }
+    loop
+  }
+  compare ycurr, ymax
+  {
+    break-if-<
+    return 0, 0
+  }
+  # we do; actually draw
+  rewind-stream stream
+  xcurr <- copy x
+  ycurr <- copy y
+  {
+    var g/eax: grapheme <- read-grapheme stream
+    compare g, 0xffffffff  # end-of-file
+    break-if-=
+    draw-grapheme screen, g, xcurr, ycurr, color
+    xcurr <- add 8  # font-width
+    compare xcurr, xmax
+    {
+      break-if-<
+      xcurr <- copy x
+      ycurr <- add 0x10  # font-height
+    }
+    loop
+  }
+  return xcurr, ycurr
+}
-- 
cgit 1.4.1-2-gfad0