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authorKartik Agaram <vc@akkartik.com>2021-01-12 00:28:25 -0800
committerKartik Agaram <vc@akkartik.com>2021-01-12 00:32:06 -0800
commit0d12f6676bab81d1d68239dcd26089612450232d (patch)
treebe66d577d24437aafffa7553ffe50d825f6183c7 /baremetal
parentbb0e67a308922fc1a1a6972b00fcc37909a028ce (diff)
downloadmu-0d12f6676bab81d1d68239dcd26089612450232d.tar.gz
7502 - baremetal text: better interface
Diffstat (limited to 'baremetal')
-rw-r--r--baremetal/501draw-text.mu9
-rw-r--r--baremetal/ex6.mu13
2 files changed, 13 insertions, 9 deletions
diff --git a/baremetal/501draw-text.mu b/baremetal/501draw-text.mu
index af165e78..0f091952 100644
--- a/baremetal/501draw-text.mu
+++ b/baremetal/501draw-text.mu
@@ -35,10 +35,11 @@ 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
+# draw text in the rectangle from (xmin, ymin) to (xmax, ymax), starting from (x, y), wrapping as necessary
 # return the next (x, y) coordinate in raster order where drawing stopped
+# that way the caller can draw more if given the same min and max bounding-box.
 # 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 {
+fn draw-text-wrapping-right-then-down screen: (addr screen), text: (addr array byte), xmin: int, ymin: int, xmax: int, ymax: int, x: int, y: 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
@@ -55,7 +56,7 @@ fn draw-text-rightward-wrapped screen: (addr screen), text: (addr array byte), x
     compare xcurr, xmax
     {
       break-if-<
-      xcurr <- copy x
+      xcurr <- copy xmin
       ycurr <- add 0x10  # font-height
     }
     loop
@@ -78,7 +79,7 @@ fn draw-text-rightward-wrapped screen: (addr screen), text: (addr array byte), x
     compare xcurr, xmax
     {
       break-if-<
-      xcurr <- copy x
+      xcurr <- copy xmin
       ycurr <- add 0x10  # font-height
     }
     loop
diff --git a/baremetal/ex6.mu b/baremetal/ex6.mu
index f0c1f896..21922dab 100644
--- a/baremetal/ex6.mu
+++ b/baremetal/ex6.mu
@@ -1,4 +1,4 @@
-# Draw ASCII text within a bounding box, while wrapping.
+# Drawing ASCII text incrementally within a bounding box.
 #
 # To build a disk image:
 #   ./translate_mu_baremetal baremetal/ex6.mu     # emits disk.img
@@ -10,8 +10,11 @@
 # Expected output: a box and text that doesn't overflow it
 
 fn main {
-  draw-box 0, 0xf, 0xf, 0x61, 0x41, 0x4
-  var x/eax: int <- copy 0
-  var y/ecx: int <- copy 0
-  x, y <- draw-text-rightward-wrapped 0, "hello from baremetal Mu!", 0x10, 0x10, 0x60, 0x40, 0xa  # xmax = 0x60, ymax = 0x40
+  draw-box 0, 0xf, 0x1f, 0x79, 0x51, 0x4
+  var x/eax: int <- copy 0x20
+  var y/ecx: int <- copy 0x20
+  x, y <- draw-text-wrapping-right-then-down 0, "hello ",     0x10, 0x20, 0x78, 0x50, x, y, 0xa  # (0x10, 0x20) -> (0x78, 0x50)
+  x, y <- draw-text-wrapping-right-then-down 0, "from ",      0x10, 0x20, 0x78, 0x50, x, y, 0xa
+  x, y <- draw-text-wrapping-right-then-down 0, "baremetal ", 0x10, 0x20, 0x78, 0x50, x, y, 0xa
+  x, y <- draw-text-wrapping-right-then-down 0, "Mu!",        0x10, 0x20, 0x78, 0x50, x, y, 0xa
 }