fb: cfb: Support memory constrainted system by partial frame transferring

doc/hardware/peripherals/display/index.rst

@@ -25,7 +25,7 @@ BBC micro:bit Display
 
 .. doxygengroup:: mb_display
 
-Monochrome Character Framebuffer
-================================
+Compact Framebuffer APIs
+========================
 
-.. doxygengroup:: monochrome_character_framebuffer
+.. doxygengroup:: compact_framebuffer_subsystem

doc/releases/migration-guide-3.7.rst

@@ -868,6 +868,65 @@ Flash map
   one-time cost of enabling the PSA API (:kconfig:option:`CONFIG_MBEDTLS_PSA_CRYPTO_C` for devices without TF-M).
   :github:`73511`
 
+CFB
+===
+
+* Changed API to support multiple displays.
+
+  Introduced :c:struct:`cfb_display` structure to represent a display.
+  Therefore, use :c:func:`cfb_display_init` instead of deprecated cfb_framebuffer_init.
+  cfb_framebuffer_init has been deprecated.
+
+  Added :c:func:`cfb_display_get_framebuffer` to get the framebuffer associated with a display.
+
+  The following API has changed the first argument pointer of :c:struct:`device` to
+  pointer of :c:struct:`cfb_framebuffer`.
+  Use the reference obtained with :c:func:`cfb_display_get_framebuffer` above.
+
+  * :c:func:`cfb_print`
+  * :c:func:`cfb_draw_text`
+  * :c:func:`cfb_draw_point`
+  * :c:func:`cfb_draw_line`
+  * :c:func:`cfb_draw_rect`
+  * :c:func:`cfb_invert_area`
+  * :c:func:`cfb_set_kerning`
+  * :c:func:`cfb_clear` (renamed from `cfb_framebuffer_clear`)
+  * :c:func:`cfb_invert` (renamed from `cfb_framebuffer_invert`)
+  * :c:func:`cfb_finalize` (renamed from `cfb_framebuffer_finalize`)
+  * :c:func:`cfb_set_font` (renamed from `cfb_framebuffer_finalize`)
+
+  :c:func:`cfb_display_alloc` can use to migrate from `cfb_framebuffer_init`.
+
+  .. code-block:: c
+
+    const struct device *dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_display));
+    struct cfb_display *disp;
+    struct cfb_framebuffer *fb;
+
+    disp = cfb_display_alloc(dev);
+    fb = cfb_display_get_framebuffer(&disp);
+    cfb_print(fb, "Hello!", 0, 0);
+
+
+  Also, please see the sample in ``samples/display/cfb``.
+
+* Remove unnecessary arguments for font-related APIs
+
+  The following API has removed the first argument pointer of :c:struct:`device`.
+  This argument was not used internally, so simply remove it.
+
+  * :c:func:`cfb_get_font_size`
+  * :c:func:`cfb_get_numof_fonts`
+
+* Change coordinate specification to signed integer
+
+  Change the following function arguments and structure fields used to specify
+  coordinates to signed integers.
+
+  * :c:func:`cfb_print`
+  * :c:func:`cfb_invert_area`
+  * :c:struct:`cfb_position`
+
 hawkBit
 =======
 

samples/boards/reel_board/mesh_badge/prj.conf

@@ -60,7 +60,7 @@ CONFIG_SPI_ASYNC=y
 CONFIG_HEAP_MEM_POOL_SIZE=16384
 CONFIG_DISPLAY=y
 
-CONFIG_CHARACTER_FRAMEBUFFER=y
+CONFIG_CFB=y
 
 CONFIG_BT_SETTINGS=y
 CONFIG_FLASH=y

samples/boards/reel_board/mesh_badge/src/reel_board.c

@@ -55,6 +55,7 @@ struct font_info {
 #define STAT_COUNT 128
 
 static const struct device *const epd_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_display));
+static struct cfb_display *epd_disp;
 static bool pressed;
 static uint8_t screen_id = SCREEN_MAIN;
 static struct k_work_delayable epd_work;
@@ -74,11 +75,12 @@ struct k_work_delayable led_timer;
 static size_t print_line(enum font_size font_size, int row, const char *text,
 			 size_t len, bool center)
 {
+	struct cfb_framebuffer *fb = cfb_display_get_framebuffer(epd_disp);
 	uint8_t font_height, font_width;
 	uint8_t line[fonts[FONT_SMALL].columns + 1];
 	int pad;
 
-	cfb_framebuffer_set_font(epd_dev, font_size);
+	cfb_set_font(fb, font_size);
 
 	len = MIN(len, fonts[font_size].columns);
 	memcpy(line, text, len);
@@ -90,9 +92,9 @@ static size_t print_line(enum font_size font_size, int row, const char *text,
 		pad = 0;
 	}
 
-	cfb_get_font_size(epd_dev, font_size, &font_width, &font_height);
+	cfb_get_font_size(font_size, &font_width, &font_height);
 
-	if (cfb_print(epd_dev, line, font_width * pad, font_height * row)) {
+	if (cfb_print(fb, line, font_width * pad, font_height * row)) {
 		printk("Failed to print a string\n");
 	}
 
@@ -134,9 +136,10 @@ void board_blink_leds(void)
 
 void board_show_text(const char *text, bool center, k_timeout_t duration)
 {
+	struct cfb_framebuffer *fb = cfb_display_get_framebuffer(epd_disp);
 	int i;
 
-	cfb_framebuffer_clear(epd_dev, false);
+	cfb_clear(fb, false);
 
 	for (i = 0; i < 3; i++) {
 		size_t len;
@@ -156,7 +159,7 @@ void board_show_text(const char *text, bool center, k_timeout_t duration)
 		}
 	}
 
-	cfb_framebuffer_finalize(epd_dev);
+	cfb_finalize(fb);
 
 	if (!K_TIMEOUT_EQ(duration, K_FOREVER)) {
 		k_work_reschedule(&epd_work, duration);
@@ -267,12 +270,13 @@ void board_add_heartbeat(uint16_t addr, uint8_t hops)
 
 static void show_statistics(void)
 {
+	struct cfb_framebuffer *fb = cfb_display_get_framebuffer(epd_disp);
 	int top[4] = { -1, -1, -1, -1 };
 	int len, i, line = 0;
 	struct stat *stat;
 	char str[32];
 
-	cfb_framebuffer_clear(epd_dev, false);
+	cfb_clear(fb, false);
 
 	len = snprintk(str, sizeof(str),
 		       "Own Address: 0x%04x", mesh_get_addr());
@@ -335,16 +339,17 @@ static void show_statistics(void)
 		}
 	}
 
-	cfb_framebuffer_finalize(epd_dev);
+	cfb_finalize(fb);
 }
 
 static void show_sensors_data(k_timeout_t interval)
 {
+	struct cfb_framebuffer *fb = cfb_display_get_framebuffer(epd_disp);
 	struct sensor_value val[3];
 	uint8_t line = 0U;
 	uint16_t len = 0U;
 
-	cfb_framebuffer_clear(epd_dev, false);
+	cfb_clear(fb, false);
 
 	/* hdc1010 */
 	if (get_hdc1010_val(val)) {
@@ -386,7 +391,7 @@ static void show_sensors_data(k_timeout_t interval)
 	len = snprintf(str_buf, sizeof(str_buf), "Proximity:%d\n", val[1].val1);
 	print_line(FONT_SMALL, line++, str_buf, len, false);
 
-	cfb_framebuffer_finalize(epd_dev);
+	cfb_finalize(fb);
 
 	k_work_reschedule(&epd_work, interval);
 
@@ -584,17 +589,22 @@ void board_refresh_display(void)
 
 int board_init(void)
 {
+	struct cfb_framebuffer *fb;
+
 	if (!device_is_ready(epd_dev)) {
 		printk("%s: device not ready.\n", epd_dev->name);
 		return -ENODEV;
 	}
 
-	if (cfb_framebuffer_init(epd_dev)) {
+	epd_disp = cfb_display_alloc(epd_dev);
+	if (!epd_disp) {
 		printk("Framebuffer initialization failed\n");
 		return -EIO;
 	}
 
-	cfb_framebuffer_clear(epd_dev, true);
+	fb = cfb_display_get_framebuffer(epd_disp);
+
+	cfb_clear(fb, true);
 
 	if (configure_button()) {
 		printk("Failed to configure button\n");

samples/subsys/display/cfb/Kconfig

@@ -0,0 +1,16 @@
+# Copyright (c) 2024 TOKITA Hiroshi
+# SPDX-License-Identifier: Apache-2.0
+
+mainmenu "CFB Sample Application"
+
+config CFB_SAMPLE_TRANSFER_BUFFER_SIZE
+	int "Buffer size for image transfer"
+	default 0
+	help
+	  Dynamically allocate display object if set 0 to this option,
+
+config CFB_SAMPLE_COMMAND_BUFFER_SIZE
+	int "Buffer size for store commands"
+	default 0
+
+source "Kconfig.zephyr"

samples/subsys/display/cfb/README.rst

@@ -1,20 +1,20 @@
-.. zephyr:code-sample:: character-frame-buffer
-   :name: Character frame buffer
-   :relevant-api: monochrome_character_framebuffer
+.. zephyr:code-sample:: cfb-sample
+   :name: Compact Framebuffer subsystem sample
+   :relevant-api: compact_framebuffer_subsystem
 
-   Display character strings using the Character Frame Buffer (CFB).
+   Display character strings using the Compact Framebuffer (CFB) subsystem.
 
 Overview
 ********
 
-This sample displays character strings using the Character Frame Buffer
-(CFB) subsystem framework.
+This sample displays character strings using the Compact Framebuffer
+(CFB) subsystem.
 
 Requirements
 ************
 
-This sample requires a supported board and CFB-supporting
-display, such as the :ref:`reel_board`.
+This sample requires a board that have a display,
+such as the :ref:`reel_board`.
 
 Building and Running
 ********************

samples/subsys/display/cfb/boards/longan_nano.conf

@@ -0,0 +1,3 @@
+CONFIG_HEAP_MEM_POOL_SIZE=4096
+CONFIG_CFB_SAMPLE_TRANSFER_BUFFER_SIZE=6400
+CONFIG_CFB_SAMPLE_COMMAND_BUFFER_SIZE=128

samples/subsys/display/cfb/boards/native_sim.conf

@@ -0,0 +1,3 @@
+CONFIG_STDOUT_CONSOLE=n
+CONFIG_HEAP_MEM_POOL_SIZE=1244160
+CONFIG_SDL_DISPLAY_DEFAULT_PIXEL_FORMAT_MONO01=y

samples/subsys/display/cfb/boards/native_sim_64.conf

@@ -0,0 +1,3 @@
+CONFIG_STDOUT_CONSOLE=n
+CONFIG_HEAP_MEM_POOL_SIZE=1244160
+CONFIG_SDL_DISPLAY_DEFAULT_PIXEL_FORMAT_MONO01=y

samples/subsys/display/cfb/prj.conf

@@ -7,4 +7,4 @@ CONFIG_DISPLAY=y
 CONFIG_LOG=y
 
 CONFIG_CFB_LOG_LEVEL_DBG=y
-CONFIG_CHARACTER_FRAMEBUFFER=y
+CONFIG_CFB=y

samples/subsys/display/cfb/sample.yaml

@@ -2,7 +2,7 @@ common:
   harness: display
   tags: display
 sample:
-  description: Character framebuffer test
+  description: Compact Framebuffer Subsystem test
   name: cfb sample
 tests:
   sample.display.cfb.ssd1306: