Make the microui demo window properly resizable (TIGR_AUTO)

TIGR_FIXED kept the bitmap at a fixed size and letterboxed it, so resizing
the window just recentred the same-size UI and stepped between integer
scales. TIGR_2X cropped the bitmap when 2X did not fit the screen (the eaten
title).

Use TIGR_AUTO so tigr resizes the bitmap to match the window (1:1); the UI
is drawn on the full canvas and resizing behaves like a normal resizable
window. Render now clips/clears using bmp^.w / bmp^.h instead of the
compile-time size. Verified by resizing the live X11 window to 1200x820.

modula2/ANALYSIS.md

@@ -348,7 +348,10 @@ The demo is rendered by tigr (not SDL): `COMMAND_RECT` -> `tigrFillRect`,
 - The demo created its window with `TIGR_2X`, which forces a 2X scale
   (1600x1200 for the 800x600 bitmap). On a screen whose client area is
   shorter than that, tigr crops the bitmap, cutting off the top rows of the
-  framebuffer - which is what "ate" the window title. `TIGR_FIXED` is used
-  instead: tigr then picks the largest integer scale that fits the display,
-  so nothing is ever cropped (on a 1080p screen it settles on 1X, on larger
-  screens on 2X or more).
+  framebuffer - which is what "ate" the window title. `TIGR_FIXED` avoided
+  the crop but letterboxes the fixed bitmap (resizing just recentres it and
+  jumps between integer scales). The demo now uses `TIGR_AUTO`: tigr resizes
+  the bitmap to match the window (1:1), so the UI draws on the full, growing
+  canvas and resizing behaves like a normal resizable window. The renderer
+  must use `bmp^.w` / `bmp^.h` (not the compile-time size) for its clip and
+  clear.

modula2/MICROUI-PORT.md

@@ -58,9 +58,12 @@ was run under X11 and the headless test renders an identical layout to PNG.
   `tigrRect` (1px outline) + `tigrFillRect` (interior). Using `tigrFillRect`
   alone shrinks every rect by one pixel and makes all 1px borders (window and
   control outlines) disappear.
-- The demo window uses `TIGR_FIXED`, not `TIGR_2X`: forcing a scale larger
-  than the screen makes tigr crop the framebuffer (which cuts the title row).
-  `TIGR_FIXED` lets tigr choose the largest integer scale that fits.
+- The demo window uses `TIGR_AUTO`: tigr resizes the bitmap to match the
+  window (1:1), so the framebuffer is never cropped or letterboxed and
+  resizing works like a normal resizable window. Forcing a scale with
+  `TIGR_2X` crops the bitmap when it doesn't fit the screen (that cut the
+  window title row), and `TIGR_FIXED` letterboxes it. The renderer uses
+  `bmp^.w`/`bmp^.h` for its clip and clear.
 
 ## GNU Modula-2 16.0.1 issues worked around
 

modula2/examples/microui-demo/microui-demo.mod

@@ -19,7 +19,7 @@ FROM tigr IMPORT TigrPtr, tigrWindow, tigrFree, tigrClosed, tigrClear,
                  tigrKeyDown, tigrKeyHeld, tigrReadChar, tigrTime,
                  tigrEncodeUTF8, tigrClip, tigrError,
                  TK_ESCAPE, TK_LSHIFT, TK_RSHIFT, TK_LCONTROL, TK_RCONTROL,
-                 TK_LALT, TK_RALT, TK_RETURN, TK_BACKSPACE, TIGR_FIXED;
+                 TK_LALT, TK_RALT, TK_RETURN, TK_BACKSPACE, TIGR_AUTO;
 FROM helper IMPORT tigrRGB, tigrRGBA;
 FROM microuiHelpers IMPORT BITAND, IntToStr, HexByte;
 IMPORT microui;
@@ -205,7 +205,7 @@ PROCEDURE Render;
         icp : IconCommandPtr;
         ccp : ClipCommandPtr;
 BEGIN
-    tigrClip(bmp, 0, 0, VAL(CARDINAL, WIN_W), VAL(CARDINAL, WIN_H));
+    tigrClip(bmp, 0, 0, bmp^.w, bmp^.h);
     tigrClear(bmp, tigrRGBA(ClampByte(bg[0]), ClampByte(bg[1]),
                             ClampByte(bg[2]), VAL(BYTE, 255)));
     cmd := NIL;
@@ -225,7 +225,7 @@ BEGIN
             SetClipI(ccp^.rect)
         END
     END;
-    tigrClip(bmp, 0, 0, VAL(CARDINAL, WIN_W), VAL(CARDINAL, WIN_H))
+    tigrClip(bmp, 0, 0, bmp^.w, bmp^.h)
 END Render;
 
 (*========================================================================*)
@@ -544,7 +544,7 @@ END LogWindow;
 (*========================================================================*)
 
 BEGIN
-    bmp := tigrWindow(WIN_W, WIN_H, "microui + tigr (Modula-2)", TIGR_FIXED);
+    bmp := tigrWindow(WIN_W, WIN_H, "microui + tigr (Modula-2)", TIGR_AUTO);
     IF bmp = NIL THEN
         tigrError(NIL, "Cannot create window")
     END;