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introduced compiler switch SMOOTH_FONT_OVERRIDE_BG 

When defined, smooth font clears out the background while drawing a glyph.
This approach takes the balance between memory consumption (sprites) and flicker (blank out complete rectangle before drawing new string).
This commit is contained in:
Gerd Müller 2021-02-12 18:36:43 +01:00
parent 6f2c5f7301
commit 9555868eda
1 changed files with 62 additions and 4 deletions
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60
Extensions/Smooth_font.cpp
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@ -365,7 +365,13 @@ void TFT_eSPI::drawGlyph(uint16_t code)
if (code < 0x21) if (code < 0x21)
{ {
if (code == 0x20) { if (code == 0x20) {
//if (fg!=bg) fillRect(cursor_x, cursor_y, gFont.spaceWidth, gFont.yAdvance, bg);
#ifdef SMOOTH_FONT_OVERRIDE_BG
if (fg!=bg) fillRect(cursor_x, cursor_y, gFont.spaceWidth, gFont.yAdvance, bg);
#endif
cursor_x += gFont.spaceWidth; cursor_x += gFont.spaceWidth;
return; return;
} }
@ -414,6 +420,19 @@ void TFT_eSPI::drawGlyph(uint16_t code)
//if (fg!=bg) fillRect(cursor_x, cursor_y, gxAdvance[gNum], gFont.yAdvance, bg); //if (fg!=bg) fillRect(cursor_x, cursor_y, gxAdvance[gNum], gFont.yAdvance, bg);
#ifdef SMOOTH_FONT_OVERRIDE_BG
if (gdY[gNum] < (2 * (gFont.ascent + gFont.descent)))
{
// strange condition, explanation see below
for (int y = 0; y < (gFont.maxAscent - gdY[gNum]); ++y)
{
drawFastHLine(cursor_x, cursor_y + y, gxAdvance[gNum], bg);
}
}
#endif
for (int y = 0; y < gHeight[gNum]; y++) for (int y = 0; y < gHeight[gNum]; y++)
{ {
#ifdef FONT_FS_AVAILABLE #ifdef FONT_FS_AVAILABLE
@ -432,6 +451,16 @@ void TFT_eSPI::drawGlyph(uint16_t code)
} }
} }
#endif #endif
#ifdef SMOOTH_FONT_OVERRIDE_BG
if (gdY[gNum] < (2 * (gFont.ascent + gFont.descent)))
{
drawFastHLine(cursor_x, y + cy, gxAdvance[gNum], bg);
}
#endif
for (int x = 0; x < gWidth[gNum]; x++) for (int x = 0; x < gWidth[gNum]; x++)
{ {
#ifdef FONT_FS_AVAILABLE #ifdef FONT_FS_AVAILABLE
@ -466,6 +495,35 @@ void TFT_eSPI::drawGlyph(uint16_t code)
if (dl) { drawFastHLine( xs, y + cy, dl, fg); dl = 0; } if (dl) { drawFastHLine( xs, y + cy, dl, fg); dl = 0; }
} }
#ifdef SMOOTH_FONT_OVERRIDE_BG
if (gdY[gNum] == (2 * (gFont.ascent + gFont.descent)))
{
// odd, unexpected situation,
// happens with an unicode special space character (not 0x20)
// with no pixels in it
// e.g. Six-Per-Em Space U+2006
//
// With NotoSans Regular, size 50, I got the following values:
// ascent: 38, maxAscent: 38, maxDescent: 12, descent: 12
// gxAdvance: 8, gdX: 4294967246
// gHeight: 1, gdY: 100
for (int y = 0; y < (gFont.ascent + gFont.descent); ++y)
{
drawFastHLine(cursor_x, y + cursor_y, gxAdvance[gNum], bg);
}
}
else
{
for (int y = 0; y < (gFont.descent - (gHeight[gNum] - gdY[gNum])); ++y)
{
drawFastHLine(cursor_x, y + cursor_y + gFont.ascent + (gHeight[gNum] - gdY[gNum]), gxAdvance[gNum], bg);
}
}
#endif
if (pbuffer) free(pbuffer); if (pbuffer) free(pbuffer);
cursor_x += gxAdvance[gNum]; cursor_x += gxAdvance[gNum];
endWrite(); endWrite();