Added POV image effect

Setup is really easy, after first boot and WiFi/LEDs setup:
go to wled.local/edit and upload a couple image to WLed's filesystem.
Only PNG is supported right now, further support for GIF is planned.
The image should be as wide as the 1D segment you want to apply to.

When done, go to the Effect page on the UI, select "POV Image" effect.

You could also update the image with a post to the JSON-API like this:
curl -X POST http://[wled]/json/state -d '{"seg":{"id":0,"fx":114,"f":"/axel.png"}}'

The segment should move at around 120RPM (that's 2revolutions per seconds) for an image to showup.
More informations and pictures here : https://lumina.toys

platformio_override.sample.ini

@@ -29,6 +29,8 @@ lib_deps = ${esp8266.lib_deps}
 ;  ;gmag11/QuickESPNow @ ~0.7.0 # will also load QuickDebug
 ;  https://github.com/blazoncek/QuickESPNow.git#optional-debug  ;; exludes debug library
 ;  ${esp32.AR_lib_deps} ;; used for USERMOD_AUDIOREACTIVE
+;  bitbank2/PNGdec@^1.0.1 ;; used for POV display uncomment following
+
 build_unflags = ${common.build_unflags}
 build_flags = ${common.build_flags} ${esp8266.build_flags}
 ;
@@ -152,6 +154,8 @@ build_flags = ${common.build_flags} ${esp8266.build_flags}
 ;   -D TACHO_PIN=33
 ;   -D PWM_PIN=32
 ;
+;  Use POV Display usermod
+;   -D USERMOD_POV_DISPLAY
 ; Use built-in or custom LED as a status indicator (assumes LED is connected to GPIO16)
 ;   -D STATUSLED=16
 ;   

usermods/pov_display/usermod_pov_display.h

@@ -0,0 +1,85 @@
+#pragma once
+#include "wled.h"
+#include <PNGdec.h>
+
+void * openFile(const char *filename, int32_t *size) {
+    f = WLED_FS.open(filename);
+    *size = f.size();
+    return &f;
+}
+
+void closeFile(void *handle) {
+    if (f) f.close();
+}
+
+int32_t readFile(PNGFILE *pFile, uint8_t *pBuf, int32_t iLen)
+{
+    int32_t iBytesRead;
+    iBytesRead = iLen;
+    File *f = static_cast<File *>(pFile->fHandle);
+    // Note: If you read a file all the way to the last byte, seek() stops working
+    if ((pFile->iSize - pFile->iPos) < iLen)
+	iBytesRead = pFile->iSize - pFile->iPos - 1; // <-- ugly work-around
+    if (iBytesRead <= 0)
+	return 0;
+    iBytesRead = (int32_t)f->read(pBuf, iBytesRead);
+    pFile->iPos = f->position();
+    return iBytesRead;
+}
+
+int32_t seekFile(PNGFILE *pFile, int32_t iPosition)
+{
+    int i = micros();
+    File *f = static_cast<File *>(pFile->fHandle);
+    f->seek(iPosition);
+    pFile->iPos = (int32_t)f->position();
+    i = micros() - i;
+    return pFile->iPos;
+}
+
+void draw(PNGDRAW *pDraw) {
+    uint16_t usPixels[SEGLEN];
+    png.getLineAsRGB565(pDraw, usPixels, PNG_RGB565_LITTLE_ENDIAN, 0xffffffff);
+    for(int x=0; x < SEGLEN; x++) {
+	uint16_t color = usPixels[x];
+	byte r = ((color >> 11) & 0x1F);
+	byte g = ((color >> 5) & 0x3F);
+	byte b = (color & 0x1F);
+	SEGMENT.setPixelColor(x, RGBW32(r,g,b,0));
+    }
+    strip.show();
+}
+
+uint16_t mode_pov_image(void) {
+    const char * filepath = SEGMENT.name;
+    int rc = png.open(filepath, openFile, closeFile, readFile, seekFile, draw);
+    if (rc == PNG_SUCCESS) {
+	rc = png.decode(NULL, 0);
+	png.close();
+	return FRAMETIME;
+    }
+    return FRAMETIME;
+}
+
+class PovDisplayUsermod : public Usermod
+{
+  public:
+    static const char _data_FX_MODE_POV_IMAGE[] PROGMEM = "POV Image@!;;;1";
+
+    PNG png;
+    File f;
+
+    void setup() {
+	strip.addEffect(255, &mode_pov_image, _data_FX_MODE_POV_IMAGE);
+    }
+
+    void loop() {
+    }
+
+    uint16_t getId()
+    {
+      return USERMOD_ID_POV_DISPLAY;
+    }
+
+    void connected() {}
+};

wled00/const.h

@@ -200,6 +200,7 @@
 #define USERMOD_ID_INA226                50     //Usermod "usermod_ina226.h"
 #define USERMOD_ID_AHT10                 51     //Usermod "usermod_aht10.h"
 #define USERMOD_ID_LD2410                52     //Usermod "usermod_ld2410.h"
+#define USERMOD_ID_POV_DISPLAY           53     //Usermod "usermod_pov_display.h"
 
 //Access point behavior
 #define AP_BEHAVIOR_BOOT_NO_CONN          0     //Open AP when no connection after boot

wled00/usermods_list.cpp

@@ -210,6 +210,10 @@
   #include "../usermods/LDR_Dusk_Dawn_v2/usermod_LDR_Dusk_Dawn_v2.h"
 #endif
 
+#ifdef USERMOD_POV_DISPLAY
+  #include "../usermods/pov_display/usermod_pov_display.h"
+#endif
+
 #ifdef USERMOD_STAIRCASE_WIPE
   #include "../usermods/stairway_wipe_basic/stairway-wipe-usermod-v2.h"
 #endif
@@ -454,4 +458,8 @@ void registerUsermods()
   #ifdef USERMOD_LD2410
   usermods.add(new LD2410Usermod());
   #endif
+
+  #ifdef USERMOD_POV_DISPLAY
+  usermods.add(new PovDisplayUsermod());
+  #endif
 }