Add OnDiskBitmap which loads pixel data straight from disk.

Also, renamed Sprite's palette to pixel_shader so it can be
anything that produces colors based on values (including color values).
Added a ColorConverter that converts RGB888 (found in bitmaps) to
RGB565 for the display.

Fixes #1182

1 files changed, 104 insertions, 0 deletions

diff --git a/shared-bindings/displayio/OnDiskBitmap.c b/shared-bindings/displayio/OnDiskBitmap.c
new file mode 100644
index 000000000..d3d413da1
--- /dev/null
+++ b/shared-bindings/displayio/OnDiskBitmap.c
@@ -0,0 +1,104 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/displayio/OnDiskBitmap.h"
+
+#include <stdint.h>
+
+#include "py/runtime.h"
+#include "supervisor/shared/translate.h"
+
+//| .. currentmodule:: displayio
+//|
+//| :class:`OnDiskBitmap` -- Loads pixels straight from disk
+//| ==========================================================================
+//|
+//| Loads values straight from disk. This minimizes memory use but can lead to
+//| much slower pixel load times. These load times may result in frame tearing where only part of
+//| the image is visible.
+//|
+//| .. warning:: This will likely be changed before 4.0.0. Consider it very experimental.
+//|
+//| It's easiest to use on a board with a built in display such as the `Hallowing M0 Express
+//| <https://www.adafruit.com/product/3900>`_.
+//|
+//| .. code-block:: Python
+//|
+//|   import board
+//|   import displayio
+//|   import time
+//|   import pulseio
+//|
+//|   backlight = pulseio.PWMOut(board.TFT_BACKLIGHT)
+//|   splash = displayio.Group()
+//|   board.DISPLAY.show(splash)
+//|
+//|   with open("/sample.bmp", "rb") as f:
+//|       odb = displayio.OnDiskBitmap(f)
+//|       face = displayio.Sprite(odb, pixel_shader=displayio.ColorConverter(), position=(0,0))
+//|       splash.append(face)
+//|       # Wait for the image to load.
+//|       board.DISPLAY.wait_for_frame()
+//|
+//|       # Fade up the backlight
+//|       for i in range(100):
+//|           backlight.duty_cycle = i * (2 ** 15) // 100
+//|           time.sleep(0.01)
+//|
+//|       # Wait forever
+//|       while True:
+//|           pass
+//|
+//| .. class:: OnDiskBitmap(file)
+//|
+//|   Create an OnDiskBitmap object with the given file.
+//|
+//|   :param file file: The open bitmap file
+//|
+STATIC mp_obj_t displayio_ondiskbitmap_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *pos_args) {
+    mp_arg_check_num(n_args, n_kw, 1, 1, false);
+
+    if (!MP_OBJ_IS_TYPE(pos_args[0], &mp_type_fileio)) {
+        mp_raise_TypeError(translate("file must be a file opened in byte mode"));
+    }
+
+    displayio_ondiskbitmap_t *self = m_new_obj(displayio_ondiskbitmap_t);
+    self->base.type = &displayio_ondiskbitmap_type;
+    common_hal_displayio_ondiskbitmap_construct(self, MP_OBJ_TO_PTR(pos_args[0]));
+
+    return MP_OBJ_FROM_PTR(self);
+}
+
+STATIC const mp_rom_map_elem_t displayio_ondiskbitmap_locals_dict_table[] = {
+};
+STATIC MP_DEFINE_CONST_DICT(displayio_ondiskbitmap_locals_dict, displayio_ondiskbitmap_locals_dict_table);
+
+const mp_obj_type_t displayio_ondiskbitmap_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_OnDiskBitmap,
+    .make_new = displayio_ondiskbitmap_make_new,
+    .locals_dict = (mp_obj_dict_t*)&displayio_ondiskbitmap_locals_dict,
+};