Document jpg conversion using ImageMagick and another example for the T-Display

examples/T-DISPLAY/jpg/alien.py

+'''
+jpg.py
+
+    Randomly draw a jpg using the fast method
+
+    The alien.jpg is from the Erik Flowers Weather Icons available from
+    https://github.com/erikflowers/weather-icons and is licensed under
+    SIL OFL 1.1
+
+    It was was converted from the wi-alien.svg icon using
+    ImageMagick's convert utility:
+
+    convert wi-alien.svg -type TrueColor alien.jpg
+'''
+
+import gc
+import random
+from machine import Pin, SPI
+import st7789
+
+gc.enable()
+gc.collect()
+
+
+def main():
+    '''
+    Decode and draw jpg on display
+    '''
+    try:
+        spi = SPI(2, baudrate=30000000, sck=Pin(18), mosi=Pin(19))
+
+        tft = st7789.ST7789(
+            spi,
+            135,
+            240,
+            reset=Pin(23, Pin.OUT),
+            cs=Pin(5, Pin.OUT),
+            dc=Pin(16, Pin.OUT),
+            backlight=Pin(4, Pin.OUT),
+            rotation=3,
+            buffer_size = 30*30*2)
+
+        # enable display and clear screen
+        tft.init()
+
+        # display jpg in random locations
+        while True:
+            tft.jpg(
+                "alien.jpg",
+                random.randint(0, tft.width() - 30),
+                random.randint(0, tft.height() - 30),
+                st7789.FAST)
+
+    finally:
+        # shutdown spi
+        spi.deinit()
+
+
+main()

st7789/st7789.c

@@ -534,6 +534,8 @@ mp_obj_t dict_lookup(mp_obj_t self_in, mp_obj_t index) {
         return elem->value;
     }
 }
+
+
 STATIC mp_obj_t st7789_ST7789_bitmap(size_t n_args, const mp_obj_t *args) {
 	st7789_ST7789_obj_t *self = MP_OBJ_TO_PTR(args[0]);
 
@@ -551,7 +553,7 @@ STATIC mp_obj_t st7789_ST7789_bitmap(size_t n_args, const mp_obj_t *args) {
 	mp_obj_dict_t *	 dict		 = MP_OBJ_TO_PTR(bitmap->globals);
 	const uint16_t	 height		 = mp_obj_get_int(mp_obj_dict_get(dict, MP_OBJ_NEW_QSTR(MP_QSTR_HEIGHT)));
 	const uint16_t	 width		 = mp_obj_get_int(mp_obj_dict_get(dict, MP_OBJ_NEW_QSTR(MP_QSTR_WIDTH)));
-    uint16_t         bitmaps     = 0;   // was = mp_obj_get_int(mp_obj_dict_get(dict, MP_OBJ_NEW_QSTR(MP_QSTR_BITMAPS)));
+    uint16_t         bitmaps     = 0;
 	const uint8_t	 bpp		 = mp_obj_get_int(mp_obj_dict_get(dict, MP_OBJ_NEW_QSTR(MP_QSTR_BPP)));
 	mp_obj_t *		 palette_arg = mp_obj_dict_get(dict, MP_OBJ_NEW_QSTR(MP_QSTR_PALETTE));
 	mp_obj_t *		 palette	 = NULL;

utils/howto-convert-to-jpg

+#
+# You can convert images to compatible jpg's by using ImageMagick's convert
+# utility by specifying the output type as TrueColor. ImageMagick downloads
+# are available from https://imagemagick.org/ for Linux, OSX, Windows and
+# other operating systems.
+#
+# The wi-alien.svg icon is from https://github.com/erikflowers/weather-icons
+# licensed under SIL OFL 1.1
+#
+
+convert wi-alien.svg -type TrueColor alien.jpg

utils/wi-alien.svg

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Generator: Adobe Illustrator 22.0.1, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
+<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
+	 viewBox="0 0 30 30" style="enable-background:new 0 0 30 30;" xml:space="preserve">
+<path d="M8.75,15.54c-1.12-2.4-0.95-4.66,0.52-6.79c1.03-1.48,2.6-2.39,4.73-2.72c0.16-0.04,0.34-0.07,0.54-0.08h0.63
+	c2.91,0.09,5.05,1.38,6.4,3.88c0.64,1.18,0.8,2.48,0.48,3.91c-0.26,1.13-0.68,2.19-1.28,3.17c-1.29,2.01-2.63,3.64-4,4.88
+	c-0.07,0.07-0.17,0.16-0.3,0.26c-0.46,0.35-0.89,0.53-1.28,0.54s-0.83-0.14-1.31-0.45c-0.29-0.17-0.53-0.37-0.74-0.59
+	C11.18,19.55,9.71,17.55,8.75,15.54z M8.86,13.33c0.02,0.11,0.05,0.25,0.09,0.44s0.07,0.32,0.09,0.4c0.28,1.26,0.86,2.23,1.73,2.93
+	c0.88,0.7,1.96,1.11,3.26,1.23c0.29,0.03,0.46,0.02,0.51-0.03s0.08-0.23,0.09-0.52c-0.01-0.08-0.03-0.21-0.05-0.39
+	c-0.02-0.18-0.04-0.31-0.06-0.39c-0.25-1.34-0.88-2.32-1.9-2.93c-0.18-0.11-0.39-0.22-0.62-0.34s-0.44-0.2-0.61-0.27
+	c-0.17-0.07-0.4-0.16-0.69-0.27c-0.29-0.11-0.5-0.19-0.63-0.25c-0.16-0.06-0.42-0.1-0.8-0.11C8.95,12.83,8.81,13,8.86,13.33z
+	 M15.66,17.73c-0.02,0.31,0,0.49,0.06,0.56c0.07,0.07,0.25,0.08,0.55,0.04c0.38-0.04,0.78-0.12,1.2-0.22
+	c1.07-0.27,1.94-0.84,2.62-1.71c0.34-0.41,0.6-0.86,0.77-1.34s0.34-1.05,0.47-1.72c0.05-0.23,0.04-0.38-0.03-0.46
+	c-0.07-0.08-0.22-0.11-0.44-0.08c-0.59,0.1-1.12,0.23-1.59,0.4c-1.15,0.43-2.02,1.01-2.62,1.74C16.05,15.68,15.72,16.6,15.66,17.73z
+	"/>
+</svg>