Fix FM step change from web UI; add FM grid to web spectrum/ruler

Web UI: stepSel.onchange now sends fm_step command to server when in FM
mode; option values stay in Hz so tuneStep works unchanged.
WebServer: add fm_step command handler and OnFMStep callback.
MainForm: wire WebOnFMStep -> SyncWebFMStep -> SetFMStep + SaveCurrentBand.

Web spectrum/ruler: vertical FM-step grid lines in drawSpec; FM-aligned
ticks and labels in drawRuler with auto label-density (short ticks between
labeled lines, measureText-based labelMult to prevent overlap).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

MainForm.pas

@@ -564,6 +564,7 @@ type
     procedure WebOnFreqA(Hz: Double);
     procedure WebOnAttn(Idx: Integer);
     procedure WebOnTun(On_: Boolean);
+    procedure WebOnFMStep(Idx: Integer);
     procedure WebOnMic(Samples: PSingle; Count: Integer);
     procedure WebOnXvtrBand(Idx: Integer);
     // Synchronize-обёртки (выполняются в UI-потоке)
@@ -593,6 +594,7 @@ type
     procedure SyncWebFreqA;
     procedure SyncWebAttn;
     procedure SyncWebTun;
+    procedure SyncWebFMStep;
     // --- CAT callbacks -------------------------------------------------------
     function  CATGetVfoA:       Double;
     function  CATGetVfoB:       Double;
@@ -1257,6 +1259,7 @@ begin
   FWebServer.OnFreqA     := WebOnFreqA;
   FWebServer.OnAttn      := WebOnAttn;
   FWebServer.OnTun       := WebOnTun;
+  FWebServer.OnFMStep    := WebOnFMStep;
   FWebServer.OnWebMic    := WebOnMic;
   FWebServer.OnXvtrBand  := WebOnXvtrBand;
   if FWebEnabled then FWebServer.Start;
@@ -5851,6 +5854,19 @@ begin
   FNetwork.SetStepAtten(FAtten * 10);
 end;
 
+procedure TMainForm.WebOnFMStep(Idx: Integer);
+begin
+  FWebSyncInt := Idx;
+  FWebSyncM   := SyncWebFMStep;
+  TThread.Synchronize(nil, FWebSyncM);
+end;
+
+procedure TMainForm.SyncWebFMStep;
+begin
+  SetFMStep(Max(0, Min(FM_STEP_COUNT - 1, FWebSyncInt)));
+  SaveCurrentBand;
+end;
+
 procedure TMainForm.WebOnTun(On_: Boolean);
 begin
   FWebSyncBool := On_;

WebPageHtml.pas

@@ -605,11 +605,28 @@ begin
 
     'function drawRuler(){const w=rulerCv.clientWidth,h=rulerCv.clientHeight;rctx.fillStyle="#0c1210";rctx.fillRect(0,0,w,h);' +
     'const st=localCenter-localSpan/2;' +
-    'for(let i=0;i<=8;i++){const x=i*w/8,f=st+i*localSpan/8;rctx.strokeStyle="#2a3a2e";rctx.lineWidth=1;rctx.beginPath();rctx.moveTo(x+.5,0);rctx.lineTo(x+.5,7);rctx.stroke();rctx.fillStyle="#7a9a80";rctx.font="10px monospace";const t=(f/1e6).toFixed(3);rctx.fillText(t,x-14,21);}' +
+    'const isFM=(cur.mode===5),fmStep=FM_STEP_HZ[fmStepIdx];' +
+    'if(isFM&&fmStep>0){' +
+    'const pxPerStep=w*fmStep/localSpan;' +
+    'const labelMult=Math.max(1,Math.ceil((rctx.measureText("000.000").width+6)/pxPerStep));' +
+    'const firstN=Math.ceil(st/fmStep);' +
+    'for(let n=firstN;n*fmStep<=localCenter+localSpan/2+0.5;n++){' +
+    'const f=n*fmStep,x=(f-st)/localSpan*w;if(x<0||x>=w)continue;' +
+    'rctx.strokeStyle="#2a3a2e";rctx.lineWidth=1;rctx.beginPath();rctx.moveTo(x+.5,0);' +
+    'if((n%labelMult)===0){rctx.lineTo(x+.5,7);rctx.stroke();rctx.fillStyle="#7a9a80";rctx.font="10px monospace";const t=(f/1e6).toFixed(3);rctx.fillText(t,x-rctx.measureText(t).width/2,21);}' +
+    'else{rctx.lineTo(x+.5,4);rctx.stroke();}}}' +
+    'else{for(let i=0;i<=8;i++){const x=i*w/8,f=st+i*localSpan/8;rctx.strokeStyle="#2a3a2e";rctx.lineWidth=1;rctx.beginPath();rctx.moveTo(x+.5,0);rctx.lineTo(x+.5,7);rctx.stroke();rctx.fillStyle="#7a9a80";rctx.font="10px monospace";const t=(f/1e6).toFixed(3);rctx.fillText(t,x-14,21);}}' +
     'const vxr=hzToX(activeVfoHz(),w);rctx.strokeStyle="#60d070";rctx.lineWidth=1;rctx.beginPath();rctx.moveTo(vxr+.5,0);rctx.lineTo(vxr+.5,h);rctx.stroke();}' +
 
     'function drawSpec(bins){const w=specCv.clientWidth,h=specCv.clientHeight;sctx.fillStyle="#050a05";sctx.fillRect(0,0,w,h);' +
     'for(let i=1;i<5;i++){const y=i*h/5;sctx.strokeStyle="#121e12";sctx.lineWidth=1;sctx.beginPath();sctx.moveTo(0,y);sctx.lineTo(w,y);sctx.stroke();}' +
+    'if(cur.mode===5&&FM_STEP_HZ[fmStepIdx]>0){' +
+    'const fmSt=FM_STEP_HZ[fmStepIdx],st2=localCenter-localSpan/2;' +
+    'const pxSt=w*fmSt/localSpan,gm=Math.max(1,Math.ceil(4/pxSt));' +
+    'const fn=Math.ceil(st2/fmSt);' +
+    'for(let n=fn;n*fmSt<=localCenter+localSpan/2+0.5;n++){' +
+    'if((n%gm)!==0)continue;const x=(n*fmSt-st2)/localSpan*w;' +
+    'if(x<0||x>=w)continue;sctx.strokeStyle="#121e12";sctx.lineWidth=1;sctx.beginPath();sctx.moveTo(x+.5,0);sctx.lineTo(x+.5,h);sctx.stroke();}}' +
     'if(!bins?.length){drawMk(sctx,w,h);return;}' +
     'if(specSm.length!==bins.length)specSm=new Array(bins.length).fill(-130);' +
     'const avf=activeVfoHz();const[fl,fh]=fltLH(),x1=hzToX(avf+fl,w),x2=hzToX(avf+fh,w);' +
@@ -649,8 +666,10 @@ begin
     'function syncStepSel(){const isFM=(cur.mode===5);const sel=q("stepSel");if(!sel)return;' +
     'if(isFM&&!inFMStep){lastHFStep=+sel.value||100;sel.innerHTML="";' +
     'FM_STEP_LBL.forEach((l,i)=>{const o=document.createElement("option");o.value=FM_STEP_HZ[i];o.textContent=l;sel.appendChild(o);});' +
-    'sel.value=FM_STEP_HZ[fmStepIdx];inFMStep=true;}' +
-    'else if(!isFM&&inFMStep){sel.innerHTML=["10 Hz","100 Hz","1 kHz","10 kHz"].map((l,i)=>`<option value="${[10,100,1000,10000][i]}">${l}</option>`).join("");' +
+    'sel.value=FM_STEP_HZ[fmStepIdx];' +
+    'sel.onchange=function(){if(!inFMStep)return;const hz=+sel.value;const idx=FM_STEP_HZ.indexOf(hz);if(idx>=0){fmStepIdx=idx;ws2({cmd:"fm_step",idx:idx});};};' +
+    'inFMStep=true;}' +
+    'else if(!isFM&&inFMStep){sel.onchange=null;sel.innerHTML=["10 Hz","100 Hz","1 kHz","10 kHz"].map((l,i)=>`<option value="${[10,100,1000,10000][i]}">${l}</option>`).join("");' +
     'sel.value=lastHFStep;inFMStep=false;}' +
     'else if(isFM){sel.value=FM_STEP_HZ[fmStepIdx];}}' +
     'function tuneStep(e){const s=+q("stepSel").value||100;if(e.ctrlKey&&e.shiftKey)return 1000000;if(e.ctrlKey)return 1000;if(e.shiftKey)return 10;return s;}' +

WebServer.pas

@@ -136,6 +136,7 @@ type
   TWebCmdFreqA     = procedure(Hz: Double) of object;
   TWebCmdAttn      = procedure(Idx: Integer) of object;
   TWebCmdTun       = procedure(On_: Boolean) of object;
+  TWebCmdFMStep    = procedure(Idx: Integer) of object;
   // XVTR-band: web клиент кликнул кнопку трансвертера (Idx 0..CFG_XVTR_COUNT-1).
   // Idx=-1 — выход в HF.
   TWebCmdXvtrBand  = procedure(Idx: Integer) of object;
@@ -244,6 +245,7 @@ type
     FOnAttn:      TWebCmdAttn;
     FAttnIdx:     Integer;
     FOnTun:       TWebCmdTun;
+    FOnFMStep:    TWebCmdFMStep;
     FTuning:      Boolean;
     FDuplex:         Boolean;
     FFreqMhzDigits:  Integer;     // 3=999MHz, 4=9.999GHz, 5=99.999GHz
@@ -334,6 +336,7 @@ type
     property OnFreqA:     TWebCmdFreqA     read FOnFreqA     write FOnFreqA;
     property OnAttn:      TWebCmdAttn      read FOnAttn      write FOnAttn;
     property OnTun:       TWebCmdTun       read FOnTun       write FOnTun;
+    property OnFMStep:    TWebCmdFMStep    read FOnFMStep    write FOnFMStep;
     property OnWebMic:    TWebMicCB        read FOnWebMic    write FOnWebMic;
   end;
 
@@ -1184,6 +1187,14 @@ begin
     if Idx > 2 then Idx := 2;
     FStateLock.Enter; FAttnIdx := Idx; FStateLock.Leave;
     if Assigned(FOnAttn) then FOnAttn(Idx);
+  end
+  else if Cmd = 'fm_step' then
+  begin
+    Idx := JsonGetInt(Json, 'idx', FFMStepIdx);
+    if Idx < 0 then Idx := 0;
+    if Idx > 3 then Idx := 3;
+    FStateLock.Enter; FFMStepIdx := Idx; FStateLock.Leave;
+    if Assigned(FOnFMStep) then FOnFMStep(Idx);
   end;
 end;