Allow the fixed fonts to be scaled up.

On larger displays, the two built in fonts are almost invisible.
One possible solution is to supply some larger fonts.

Another approach is to do, like several TFT display drivers do and allow you to scale the system fixed fonts up to a larger size.  Decided this was the easiest approach, and did a quick implementation of it.  Like the Adafruit displays, I allowed you to set different scale factors for X and Y.

I added a scaledBitmap function which is a modified version of the current bitmap function.  I also changed all of the text functions to use it.  I left the unscalled version of the API, although I have it simply call the scaled version with scales 1 and 1, as since these methods are virtual, potentially some other subclasses might use and/or implement their own version.

Updated the textFontWidth and textFontHeight to multiply  the height * the scale as
the one example sketch here needs it.

I also updated the sketch to scale the canvas to take the font size into account.
This appears to work with the changes and

I have not used or tested the scroll code.  Its sizing should be updated teh same way
the test sketch was with the changes with the textFontWidth and textFontHeight changes

Update api.md

Forgot to update the AsciiDraw example sketch

Code Review requested changes

_textsize_x -> _textSizeX  (ditto for y)
setTextSize() -> textSize()

scaledBitmap -> bitmap with the extra parameters with defaults

Author: KurtE

docs/api.md

@@ -641,6 +641,41 @@ Nothing
 int h = YourScreen.textFontHeight();
 ```
 
+### `textSize()`
+
+#### Description
+
+Set a text scale factor
+
+#### Syntax
+
+```
+YourScreen.textSize(scale)
+YourScreen.textSize(scaleX, scaleY)
+```
+
+#### Parameters
+
+scale: scale factor used for both x and y
+scaleX: x scale factor
+scaleY: y scale factor
+
+#### Returns
+
+Nothing
+
+#### Example
+
+```
+YourScreen.beginDraw();
+YourScreen.clear();
+YourScreen.stroke(255, 255, 255);
+YourScreen.textFont(Font_5x7);
+YourScreen.textSize(5);
+YourScreen.text("abc", 0, 1);
+YourScreen.endDraw();
+```
+
 ### `set()`
 
 #### Description

examples/ASCIIDraw/ASCIIDraw.ino

@@ -14,8 +14,9 @@
 
 #include <ArduinoGraphics.h>
 
-const byte canvasWidth = 61;
-const byte canvasHeight = 27;
+const byte fontSize = 3;
+const byte canvasWidth = fontSize * (5 * 7) + 26;
+const byte canvasHeight = fontSize * 7 + 20;
 
 class ASCIIDrawClass : public ArduinoGraphics {
   public:
@@ -85,6 +86,7 @@ void setup() {
   ASCIIDraw.stroke('@', 0, 0);
   const char text[] = "ARDUINO";
   ASCIIDraw.textFont(Font_5x7);
+  ASCIIDraw.textSize(fontSize);
   const byte textWidth = strlen(text) * ASCIIDraw.textFontWidth();
   const byte textHeight = ASCIIDraw.textFontHeight();
   const byte textX = (canvasWidth - textWidth) / 2;

src/ArduinoGraphics.cpp

@@ -26,7 +26,9 @@
 ArduinoGraphics::ArduinoGraphics(int width, int height) :
   _width(width),
   _height(height),
-  _font(NULL)
+  _font(NULL),
+  _textSizeX(1),
+  _textSizeY(1)
 {
 }
 
@@ -241,7 +243,7 @@ void ArduinoGraphics::text(const char* str, int x, int y)
     uint8_t const c = (uint8_t)*str++;
 
     if (c == '\n') {
-      y += _font->height;
+      y += _font->height * _textSizeY;
     } else if (c == '\r') {
       x = 0;
     } else if (c == 0xc2 || c == 0xc3) {
@@ -254,10 +256,10 @@ void ArduinoGraphics::text(const char* str, int x, int y)
       }
 
       if (b) {
-        bitmap(b, x, y, _font->width, _font->height);
+        bitmap(b, x, y, _font->width, _font->height, _textSizeX, _textSizeY);
       }
 
-      x += _font->width;
+      x += _font->width * _textSizeX;
     }
   }
 }
@@ -269,38 +271,51 @@ void ArduinoGraphics::textFont(const Font& which)
 
 int ArduinoGraphics::textFontWidth() const
 {
-  return (_font ? _font->width : 0);
+  return (_font ? _font->width * _textSizeX : 0);
 }
 
 int ArduinoGraphics::textFontHeight() const
 {
-  return (_font ? _font->height : 0);
+  return (_font ? _font->height* _textSizeY : 0);
 }
 
-void ArduinoGraphics::bitmap(const uint8_t* data, int x, int y, int width, int height)
+void ArduinoGraphics::textSize(uint8_t sx, uint8_t sy)
 {
-  if (!_stroke) {
+  _textSizeX = (sx > 0)? sx : 1;
+  _textSizeY = (sy > 0)? sy : 1;
+}
+
+
+void ArduinoGraphics::bitmap(const uint8_t* data, int x, int y, int w, int h, uint8_t scale_x, uint8_t scale_y) {
+  if (!_stroke || !scale_x || !scale_y) {
     return;
   }
 
-  if ((data == NULL) || ((x + width) < 0) || ((y + height) < 0) || (x > _width) || (y > _height)) {
+  if ((data == nullptr) || ((x + (w * scale_x) < 0)) || ((y + (h * scale_y) < 0)) || (x > _width) || (y > _height)) {
     // offscreen
     return;
   }
 
-  for (int j = 0; j < height; j++) {
+  int xStart = x;
+  for (int j = 0; j < h; j++) {
     uint8_t b = data[j];
-
-    for (int i = 0; i < width; i++) {
-      if (b & (1 << (7 - i))) {
-        set(x + i, y + j, _strokeR, _strokeG, _strokeB);
-      } else {
-        set(x + i, y + j, _backgroundR, _backgroundG, _backgroundB);
+    for (uint8_t ys = 0; ys < scale_y; 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 < scale_x; xs++) set(x++, y, _strokeR, _strokeG, _strokeB);
+        } else {
+          for (uint8_t xs = 0; xs < scale_x; xs++) set(x++, y, _backgroundR, _backgroundG, _backgroundB);
+        }
+        if (x >= _width) break;
       }
+      y++;
     }
   }
 }
 
+
 void ArduinoGraphics::imageRGB(const Image& img, int x, int y, int width, int height)
 {
   const uint8_t* data = img.data();
@@ -359,7 +374,7 @@ void ArduinoGraphics::image(const Image& img, int x, int y)
 
 void ArduinoGraphics::image(const Image& img, int x, int y, int width, int height)
 {
-  if (!img || ((x + width) < 0) || ((y + height) < 0) || (x > _width) || (y > height)) {
+  if (!img || ((x + width) < 0) || ((y + height) < 0) || (x > _width) || (y > _height)) {
     // offscreen
     return;
   }
@@ -438,7 +453,7 @@ void ArduinoGraphics::endText(int scrollDirection)
       beginDraw();
       int const text_x = _textX - i;
       text(_textBuffer, text_x, _textY);
-      bitmap(_font->data[0x20], text_x - 1, _textY, 1, _font->height);
+      bitmap(_font->data[0x20], text_x - 1, _textY, 1, _font->height, _textSizeX, _textSizeY);
       endDraw();
 
       delay(_textScrollSpeed);
@@ -450,7 +465,7 @@ void ArduinoGraphics::endText(int scrollDirection)
       beginDraw();
       int const text_x = _textX - (scrollLength - i - 1);
       text(_textBuffer, text_x, _textY);
-      bitmap(_font->data[0x20], text_x - 1, _textY, 1, _font->height);
+      bitmap(_font->data[0x20], text_x - 1, _textY, 1, _font->height, _textSizeX, _textSizeY);
       endDraw();
 
       delay(_textScrollSpeed);
@@ -462,7 +477,7 @@ void ArduinoGraphics::endText(int scrollDirection)
       beginDraw();
       int const text_y = _textY - i;
       text(_textBuffer, _textX, text_y);
-      bitmap(_font->data[0x20], _textX, text_y - 1, _font->width, 1);
+      bitmap(_font->data[0x20], _textX, text_y - 1, _font->width, 1, _textSizeX, _textSizeY);
       endDraw();
 
       delay(_textScrollSpeed);
@@ -474,7 +489,7 @@ void ArduinoGraphics::endText(int scrollDirection)
       beginDraw();
       int const text_y = _textY - (scrollLength - i - 1);
       text(_textBuffer, _textX, text_y);
-      bitmap(_font->data[0x20], _textX, text_y - 1, _font->width, 1);
+      bitmap(_font->data[0x20], _textX, text_y - 1, _font->width, 1, _textSizeX, _textSizeY);
       endDraw();
 
       delay(_textScrollSpeed);

src/ArduinoGraphics.h

@@ -70,6 +70,8 @@ class ArduinoGraphics : public Print {
   virtual void text(const char* str, int x = 0, int y = 0);
   virtual void text(const String& str, int x = 0, int y = 0) { text(str.c_str(), x, y); }
   virtual void textFont(const Font& which);
+  virtual void textSize(uint8_t s) {textSize(s, s);}
+  virtual void textSize(uint8_t sx, uint8_t sy);
 
   virtual int textFontWidth() const;
   virtual int textFontHeight() const;
@@ -91,7 +93,8 @@ class ArduinoGraphics : public Print {
   virtual void textScrollSpeed(unsigned long speed = 150);
 
 protected:
-  virtual void bitmap(const uint8_t* data, int x, int y, int width, int height);
+  virtual void bitmap(const uint8_t* data, int x, int y, int w, int h, uint8_t scale_x = 1, 
+                      uint8_t scale_y = 1);
   virtual void imageRGB(const Image& img, int x, int y, int width, int height);
   virtual void imageRGB24(const Image& img, int x, int y, int width, int height);
   virtual void imageRGB16(const Image& img, int x, int y, int width, int height);
@@ -114,6 +117,8 @@ class ArduinoGraphics : public Print {
   uint8_t _textR, _textG, _textB;
   int _textX;
   int _textY;
+  uint8_t _textSizeX;
+  uint8_t _textSizeY;
   unsigned long _textScrollSpeed;
 };