Feature: Waveform loop lock

Documentation/community_features.md

@@ -67,6 +67,9 @@ Synchronization modes accessible through the "LFO SYNC" shortcut.
 ### Audio Clip View
  - ([#141]) Holding the vertical encoder down while turning the horizontal encoder will shift the clip along the underlying audio file, similar to the same interface for instrument clips.
 
+### Sample Waveform View
+ - ([#293]) When a sample has loop start and loop end points set, holding down loop start and tapping loop end will lock the loop points together. Moving one will move the other, keeping them the same distance apart. Use the same process to unlock the loop points. Use SHIFT+TURN<> to double or half the loop length.
+
 ### Takeover Mode
 
  - ([#170]) The Takeover menu consists of three modes that can be selected from:
@@ -134,3 +137,4 @@ This list includes all preprocessor switches that can alter firmware behaviour a
 [#221]: https://github.com/SynthstromAudible/DelugeFirmware/pull/221
 [#234]: https://github.com/SynthstromAudible/DelugeFirmware/pull/234
 [#282]: https://github.com/SynthstromAudible/DelugeFirmware/pull/282
+[#293]: https://github.com/SynthstromAudible/DelugeFirmware/pull/293

src/deluge/gui/ui/sample_marker_editor.cpp

@@ -51,6 +51,9 @@ extern "C" {
 
 const uint8_t zeroes[] = {0, 0, 0, 0, 0, 0, 0, 0};
 
+int loopLength = 0;
+bool loopLocked = false;
+
 SampleMarkerEditor sampleMarkerEditor{};
 
 SampleMarkerEditor::SampleMarkerEditor() {
@@ -142,10 +145,28 @@ void SampleMarkerEditor::writeValue(uint32_t value, MarkerType markerTypeNow) {
 		getCurrentSampleHolder()->startPos = value;
 	}
 	else if (markerTypeNow == MarkerType::LOOP_START) {
-		getCurrentMultisampleRange()->sampleHolder.loopStartPos = value;
+		if (loopLocked) {
+			int intendedLoopEndPos = value + loopLength;
+			if (intendedLoopEndPos <= getCurrentSampleHolder()->endPos) {
+				getCurrentMultisampleRange()->sampleHolder.loopStartPos = value;
+				getCurrentMultisampleRange()->sampleHolder.loopEndPos = intendedLoopEndPos;
+			}
+		}
+		else {
+			getCurrentMultisampleRange()->sampleHolder.loopStartPos = value;
+		}
 	}
 	else if (markerTypeNow == MarkerType::LOOP_END) {
-		getCurrentMultisampleRange()->sampleHolder.loopEndPos = value;
+		if (loopLocked) {
+			int intendedLoopStartPos = value - loopLength;
+			if (intendedLoopStartPos >= getCurrentSampleHolder()->startPos) {
+				getCurrentMultisampleRange()->sampleHolder.loopEndPos = value;
+				getCurrentMultisampleRange()->sampleHolder.loopStartPos = intendedLoopStartPos;
+			}
+		}
+		else {
+			getCurrentMultisampleRange()->sampleHolder.loopEndPos = value;
+		}
 	}
 	else if (markerTypeNow == MarkerType::END) {
 		getCurrentSampleHolder()->endPos = value;
@@ -426,6 +447,21 @@ ActionResult SampleMarkerEditor::padAction(int32_t x, int32_t y, int32_t on) {
 
 						goto ensureNotPastSampleLength;
 					}
+					else if (markerHeld == MarkerType::LOOP_START && markerPressed == MarkerType::LOOP_END) {
+						if (loopLocked == false) {
+							loopLocked = true;
+							int loopStart = getCurrentMultisampleRange()->sampleHolder.loopStartPos;
+							int loopEnd = getCurrentMultisampleRange()->sampleHolder.loopEndPos;
+							loopLength = loopEnd - loopStart;
+							numericDriver.displayPopup("LOCK");
+						}
+						else {
+							loopLocked = false;
+							loopLength = 0;
+							numericDriver.displayPopup("FREE");
+						}
+						return ActionResult::DEALT_WITH;
+					}
 
 					// Or if a loop point and they pressed the end marker, remove the loop point
 					else if (markerHeld == MarkerType::LOOP_START) {
@@ -623,6 +659,39 @@ static const uint32_t zoomUIModes[] = {UI_MODE_HOLDING_HORIZONTAL_ENCODER_BUTTON
 
 ActionResult SampleMarkerEditor::horizontalEncoderAction(int32_t offset) {
 
+	if (loopLocked && Buttons::isShiftButtonPressed()) {
+		if (offset > 0) { // turn clockwise
+			int end = getCurrentSampleHolder()->endPos;
+			int loopEnd = getCurrentMultisampleRange()->sampleHolder.loopEndPos;
+
+			if (loopEnd + loopLength < end) {
+				loopLength = loopLength * 2;
+				numericDriver.displayPopup(HAVE_OLED ? "Loop doubled" : "DOUB");
+			}
+			else {
+				numericDriver.displayPopup(HAVE_OLED ? "Loop too long" : "CANT");
+				return ActionResult::DEALT_WITH;
+			}
+		}
+		else { // turn anti-clockwise
+			if (loopLength > 2) {
+				loopLength = loopLength / 2;
+				numericDriver.displayPopup(HAVE_OLED ? "Loop halved" : "HALF");
+			}
+			else {
+				numericDriver.displayPopup(HAVE_OLED ? "Loop too short" : "CANT");
+				return ActionResult::DEALT_WITH;
+			}
+		}
+
+		int loopStart = getCurrentMultisampleRange()->sampleHolder.loopStartPos;
+		int newLoopEnd = loopStart + loopLength;
+		writeValue(newLoopEnd, MarkerType::LOOP_END);
+		uiNeedsRendering(this, 0xFFFFFFFF, 0);
+
+		return ActionResult::DEALT_WITH;
+	}
+
 	// We're quite likely going to need to read the SD card to do either scrolling or zooming
 	if (sdRoutineLock) {
 		return ActionResult::REMIND_ME_OUTSIDE_CARD_ROUTINE;