Use TIGR_FIXED for the microui demo window

TIGR_2X forced a 1600x1200 framebuffer for the 800x600 bitmap; on a display
whose client area is shorter than that, tigr crops the bitmap and the top
rows (the Demo Window title) were cut off - the "eaten top".

Use TIGR_FIXED so tigr computes the largest integer scale that fits the
screen (1X on 1080p, more on larger displays) and never crops the
framebuffer. Document the tigrFillRect interior-only behaviour and the
scaling/cropping pitfall in ANALYSIS.md / MICROUI-PORT.md.

modula2/ANALYSIS.md

@@ -344,4 +344,11 @@ The demo is rendered by tigr (not SDL): `COMMAND_RECT` -> `tigrFillRect`,
   which showed up as the top of the window being "eaten" by the title bar.
   The fix is to draw `tigrRect` (1px outline) followed by `tigrFillRect`
   (interior): together they fill the exact rectangle, with clipping and
-  alpha blending, and single-pixel rects still show.
+  alpha blending, and single-pixel rects still show.
+- 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).

modula2/MICROUI-PORT.md

@@ -58,6 +58,9 @@ 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.
 
 ## 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_2X;
+                 TK_LALT, TK_RALT, TK_RETURN, TK_BACKSPACE, TIGR_FIXED;
 FROM helper IMPORT tigrRGB, tigrRGBA;
 FROM microuiHelpers IMPORT BITAND, IntToStr, HexByte;
 IMPORT microui;
@@ -544,7 +544,7 @@ END LogWindow;
 (*========================================================================*)
 
 BEGIN
-    bmp := tigrWindow(WIN_W, WIN_H, "microui + tigr (Modula-2)", TIGR_2X);
+    bmp := tigrWindow(WIN_W, WIN_H, "microui + tigr (Modula-2)", TIGR_FIXED);
     IF bmp = NIL THEN
         tigrError(NIL, "Cannot create window")
     END;