16-bit image on SD-card¶

The 16-bit image on SD-card library saves the screen as a header file on the SD-card.

The header file is added to the source code and included in the project of the application statistically at build-time. Once the application is built, it loads the image into the frame-buffer, ready to be displayed dynamically at run-time.

Info

This method is not recommended for MCUs, as the management of the SD-card is rather slow and prone to interferences.

The image on SD-card library is available on the Commercial edition.

Configure¶

Warning

Ensure the screen is declared and initialised according to the configuration procedure.

#include "hV_File_Image16.h"

The pre-processor statement includes the file library. It should be mentioned after the statement for the screen library.

Danger

This library requires the external SD library to manage the SD-card.

Ensure the external SD library is installed and properly configured.

File_Image16 myFile(&myScreen);

The constructor File_Image16() sets the link to the screen. It should be mentioned after the constructor of the screen.

bool result = myFile.beginFileSystem(pinCS,
    portSPI,
    pinDetect,
    pinLevel);

if (result != RESULT_SUCCESS)
{
    hV_HAL_Serial_crlf();
    hV_HAL_log(LEVEL_CRITICAL, "SD-card error");
    hV_HAL_exit(1);
}

myFile.setFolder("Image");

beginFileSystem() checks an SD-card is available and initialises it.

The required parameter is

The first line sets the pin for selecting the SD-card.

It is easily provided with myScreen.getBoardPins().cardCS.

The optional parameters are

The second line sets the number of the SPI port, 0 by default;
The third line sets the pin for the detect signal, NOT_CONNECTED or -1 par default;
The fourth line sets the level of detect signal, LOW by default.

beginFileSystem() returns RESULT_SUCCESS if successful, RESULT_ERROR otherwise.

Legacy version 5

beginFileSystem() returned a boolean value, now replaced by clear constants.

setFolder() sets the name of the folder for the files, and creates it if it does not exists.

By default, the files are located under the folder img.

Use¶

Generate¶

myFile.saveScreen("File_Image16");

saveScreen() saves the screen on the SD-card as a image.

The required parameter is

The first line provides the name of the file without the .h extension.

myFile.saveWindow("Colours4",
    40, 71, 100, 50) // x y dx dy

saveWindow() save a window on a header file on the SD-card as an image.

The required parameters are

The first line provides the name of the file without the .h extension.
The second line defines the window with vector coordinates.

The coordinates are rounded as multiple of 8.

For example, the vector coordinates (70, 44, 155, 64) are changed to (70, 40, 155, 72).

The resulting header file is named Colours4.h and contains the structure Image_Colours4.

myFile.endFileSystem();

endFileSystem() closes the SD-card.

Display¶

#include "Colours4.h"

myFile.readScreen(Image_Colours4);
myScreen.flush();

The application needs to include the header file previously generated.

readScreen() loads the image into the frame-buffer, ready to be displayed.

The header file can also be read with the Serial_Image16 object, from the 16-bit image implementation on the Serial library.

Example¶

This is the core of the code from example File_Write_Image.ino.

First, generate the header file.

void displayWriteSerialImage()
{
    // Initialise
    bool result = myFile.beginFileSystem();
    if (result != RESULT_SUCCESS)
    {
        hV_HAL_log(LEVEL_ERROR, "SD-card error");
        hV_HAL_Serial_crlf();
        return;
    }

    myScreen.setOrientation(myOrientation);
    myScreen.selectFont(fontLarge);

    myScreen.clear();
    myScreen.gText(8, 8, "File Image16");
    myScreen.flush();

    // Write to SD-card
    myFile.saveScreen("File_Image16");
    wait(4);
}

The generated header file is

// Image16 as header file generated by hV_File_Image16

// SDK
#include "hV_HAL_Peripherals.h"

// Release
#ifndef FILE_IMAGE_FILE_IMAGE_RELEASE
#define FILE_IMAGE_FILE_IMAGE_RELEASE

#include "hV_Image16.h"

static const uint16_t Table_File_Image16[] =
{
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, // v= 152
    // ...
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, // v= 1
};

const image16_s Image_File_Image16 =
{
    .minWindowH = 0,
    .minWindowV = 0,
    .maxWindowH = 151,
    .maxWindowV = 151,
    .depth = 2,
    .size = 23104,
    .table = Table_File_Image16
};

#endif // FILE_IMAGE_FILE_IMAGE_RELEASE

The window uses rectangular coordinates.