ESP-IDF GFX font test

// use C++ with ESP-IDF:
extern "C" { void app_main(); }

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_system.h"
#include "esp_spiffs.h"
#include "drivers/ili9341.hpp"
#include "gfx_cpp14.hpp"

#define LCD_HOST    VSPI_HOST
#define DMA_CHAN    2
#define PIN_NUM_MISO GPIO_NUM_19
#define PIN_NUM_MOSI GPIO_NUM_23
#define PIN_NUM_CLK  GPIO_NUM_18
#define PIN_NUM_CS   GPIO_NUM_5

#define PIN_NUM_DC   GPIO_NUM_2
#define PIN_NUM_RST  GPIO_NUM_4
#define PIN_NUM_BCKL GPIO_NUM_15

// configure the spi bus. Must be done before the driver
spi_master spi_host(nullptr,
                    LCD_HOST,
                    PIN_NUM_CLK,
                    PIN_NUM_MISO,
                    PIN_NUM_MOSI,
                    GPIO_NUM_NC,
                    GPIO_NUM_NC,
                    320*240+8,
                    DMA_CHAN);

// we use the default, modest buffer - it makes things slower but uses less
// memory. it usually works fine at default but you can change it for performance
// tuning. It's the final parameter: Note that it shouldn't be any bigger than
// the DMA size
using lcd_type = ili9341<LCD_HOST,
                        PIN_NUM_CS,
                        PIN_NUM_DC,
                        PIN_NUM_RST,
                        PIN_NUM_BCKL>;

lcd_type lcd;

using lcd_color = color<typename lcd_type::pixel_type>;

void app_main(void)
{
    // we'll be loading the font from SPIFFs.
    // To embed the font instead, run the lib/gfx/tools/fontgen tool to create a header.
    // then include that header. The font will be precreated with the same name as the header
    // sans extension.

    // check to make sure SPI was initialized successfully
    if(!spi_host.initialized()) {
        printf("SPI host initialization error.\r\n");
        abort();
    }
    // mount SPIFFS
    esp_err_t ret;
    esp_vfs_spiffs_conf_t conf = {};
    conf.base_path="/spiffs";
    conf.format_if_mount_failed=false;
    conf.max_files=5;
    conf.partition_label="storage";
    ret=esp_vfs_spiffs_register(&conf);
    ESP_ERROR_CHECK(ret);

    file_stream fs("/spiffs/Bm437_Verite_9x16.FON");

    font my_font;
    if(gfx::font::result::success!=font::read(&fs,&my_font)) {
        fs.close();
        printf("Error loading font");
        return;
    }
    fs.close();

    const char* sz="test!";

    for(int i = 0;i<200;++i) {
        // drawing with a non-transparent background is significantly faster
        draw::text(lcd,{0,0,lcd.bounds().x2,lcd.bounds().y2},sz,my_font,lcd_color::white,lcd_color::black,false);
    }