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Panel_M5UnitLCD: fix ARGB image writes, reads after image writes and the first draw after reset #355

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Merged
lovyan03 merged 1 commit into from
Oct 14, 2026
Merged

Panel_M5UnitLCD: fix ARGB image writes, reads after image writes and the first draw after reset #355

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36 changes: 32 additions & 4 deletions src/lgfx/v1/panel/Panel_M5UnitLCD.inl
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Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,16 @@ namespace lgfx
startWrite(true);
_bus->writeCommand(CMD_READ_ID, 8);
} while (!(_bus->readBytes(buf, 4, true) && buf[0] == 0x77 && buf[1] == 0x89) && --retry);
// The unit answers READ_ID before it finishes starting up (about 250 ms more), and
// pixel data streamed in that period is dropped. Queue a one-pixel fill and wait until
// the unit has consumed it: a NOP is consumed at once and says nothing about drawing.
writeFillRectPreclipped(0, 0, 1, 1, 0);
_buff_free_count = 0;
retry = 4;
do
{
_check_repeat(0, 255);
} while (_buff_free_count < 255 && --retry);
}
}

Expand Down Expand Up @@ -588,15 +598,30 @@ if (bytelen != rleDecode(dest, res, bytes)*bytes) {

void Panel_M5UnitLCD::writeImageARGB(uint_fast16_t x, uint_fast16_t y, uint_fast16_t w, uint_fast16_t h, pixelcopy_t* param)
{
_set_window(x, y, x + w - 1, y);
auto buf = (uint32_t*)param->src_data;
// The unit blends ARGB itself, so source pixels are sent as they are, row by row,
// starting from the clipped source position held in param.
_set_window(x, y, x + w - 1, y + h - 1);
auto src = (const uint32_t*)param->src_data;
// bgra8888_t (argb8888_4Byte) holds the bytes in the reverse order of argb8888_t,
// so its raw value already has the byte order the unit expects.
bool swap = (param->src_depth != argb8888_4Byte);
if (!_check_repeat(CMD_WRITE_RAW_32))
{
writeCommand(CMD_WRITE_RAW_32, 1);
}
for (size_t i = 0; i < w; ++i)
for (;;)
{
_bus->writeCommand(getSwap32(buf[i]), 32);
uint32_t x32 = param->src_x32;
uint32_t y32 = param->src_y32;
for (size_t i = 0; i < w; ++i)
{
uint32_t idx = (x32 >> pixelcopy_t::FP_SCALE) + (y32 >> pixelcopy_t::FP_SCALE) * param->src_bitwidth;
_bus->writeCommand(swap ? getSwap32(src[idx]) : src[idx], 32);
x32 += param->src_x32_add;
y32 += param->src_y32_add;
}
if (!--h) { break; }
param->src_y++;
}
_raw_color = ~0u;
}
Expand All @@ -608,6 +633,9 @@ if (bytelen != rleDecode(dest, res, bytes)*bytes) {
do {
_check_repeat(0, 255);
} while (_buff_free_count < 255 && --retry);
// Always send the window: after an image write the unit returns zeros when the
// read reuses the cached column range, so CASET must not be skipped here.
_xs = _xe = _ys = _ye = INT16_MAX;
_set_window(x, y, x+w-1, y+h-1);

_bus->writeCommand(CMD_READ_RAW | ((_read_bits >> 3) & 3), 8);
Expand Down
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