Add API to set font size

[sandeepmistry]

From @tigoe:

To set. One of the big issues I've found is readability of different fonts across different screens (been testing ePaper too), so having the ability to adapt fonts and sizes is essential.

[KurtE]

Not sure if better to comment on this 5 year old Issue, or to create a new one...

I fully agree. Using the built in font code on an Arduino GIGA Display shield, the built in fonts are more or less useless.

As I mentioned up on the Forum posting:
https://forum.arduino.cc/t/arduino-h7-video-h-and-arduinographics-library-fonts/1289636/2

I am experimenting without actually updating the library, but in one of my test sketches I created a subclass of the
Arduino_H7_Video class, where I added a method:

    void textSize(uint8_t xs = 1, uint8_t ys = 0);

My test sketch including the .h and .cpp file for the sub-class are up at:
https://github.com/KurtE/Arduino_GIGA-stuff/tree/main/sketches/tft_picture_view_sd_giga_shield_24Bit

I had to replicate several of the ArduinoGraphics class as several of the member variables are marked private,
like:

    const Font* _font;
    uint8_t _strokeR, _strokeG, _strokeB;
    uint8_t _backgroundR, _backgroundG, _backgroundB;
    bool _stroke = false;

The main functions are:

void Arduino_H7_Video_Plus::text(const char* str, int x, int y) {
    if (!_font || !_stroke) {
        return;
    }
    if ((_xTextScale == 1) && (_yTextScale == 1)) {
        ArduinoGraphics::text(str, x, y);
        return;
    }

    while (*str) {
        uint8_t const c = (uint8_t)*str++;

        if (c == '\n') {
            y += _font->height * _yTextScale;
        } else if (c == '\r') {
            x = 0;
        } else if (c == 0xc2 || c == 0xc3) {
            // drop
        } else {
            const uint8_t* b = _font->data[c];

            if (b == NULL) {
                b = _font->data[0x20];
            }

            if (b) {
                scaledBitmap(b, x, y, _font->width, _font->height);
            }

            x += _font->width * _xTextScale;
        }
    }
}
void Arduino_H7_Video_Plus::scaledBitmap(const uint8_t* data, int x, int y, int w, int h) {
    if (!_stroke || !_xTextScale || !_yTextScale) {
        return;
    }

    if ((data == nullptr) || ((x + (w * _xTextScale) < 0)) || ((y + (h * _yTextScale) < 0)) || (x > width()) || (y > height())) {
        // offscreen
        return;
    }

    int xStart = x;
    for (int j = 0; j < h; j++) {
        uint8_t b = data[j];
        for (uint8_t ys = 0; ys < _yTextScale; ys++) {
            if (ys >= height()) return;  //
            x = xStart;                  // reset for each row
            for (int i = 0; i < w; i++) {
                if (b & (1 << (7 - i))) {
                    for (uint8_t xs = 0; xs < _xTextScale; xs++) set(x++, y, _strokeR, _strokeG, _strokeB);
                } else {
                    for (uint8_t xs = 0; xs < _xTextScale; xs++) set(x++, y, _backgroundR, _backgroundG, _backgroundB);
                }
                if (x >= width()) break;
            }
            y++;
        }
    }
}

I have not updated any of the other methods, that potentially could include:
textFontWidth(), textFontHeight() and the like.