Emacs Windows XBM bug

emacs-windows-xbm-bug.el

;;; -*- lexical-binding: t -*-
;; 1. Copy this code to an Emacs buffer
;; 2. M-x eval-buffer

(let ((width 90)
      (height 90)
      (tiles-column-count 3)
      (tiles-row-count 3)
      (foreground-color "red")
      (background-color "blue"))

  (let* ((tile-width (floor (/ width (float tiles-column-count))))
         (tile-height (floor (/ height (float tiles-row-count))))
         (bits (apply #'vector
                      (mapcar (lambda (init)
                                (make-bool-vector width init))
                              (make-list height nil)))))

    (let ((current-color t))
      (dotimes (row tiles-row-count)
        (dotimes (column tiles-column-count)
          (dotimes (i tile-height)
            (dotimes (j tile-width)
              (let ((y (+ (* row tile-height) i))
                    (x (+ (* column tile-width) j)))
                (aset (aref bits y) x current-color))))
          (setq current-color (not current-color)))))

    (insert-image
     (create-image bits 'xbm t
                   :width width :height height
                   :foreground foreground-color
                   :background background-color)
     " ")))