DearMQL5/Widgets/UButton.mqh
Alex David Hernandez Maturrano 78e7ae5145 feat: initial release of DearMQL5 v1.0.0 - Immediate-Mode GUI Engine for MetaTrader 5
DearMQL5 is an institutional-grade, immediate-mode graphical user interface
(GUI) engine designed from the ground up for MetaTrader 5 (MQL5), inspired by
the ergonomics and performance of Dear ImGui.

### Core Architecture & Execution Pipeline
- Immediate-Mode Paradigm: Declarative frame-based rendering pipeline with zero
  memory allocation churn during render loops and deterministic execution.
- Modular Per-Hub Canvas Surfaces (CUWindowSurface): Replaces full-screen canvas
  overlays with isolated, window-bounded CCanvas bitmaps, reducing memory usage
  by up to 93% (~570 KB vs 8.3 MB for 1080p) and preventing click-swallowing.
- 0-Cost Hardware Texture Drag Engine: Absolute-anchor drag mechanics update
  native MT5 OBJPROP_XDISTANCE and OBJPROP_YDISTANCE properties directly on
  the compositor, bypassing CPU rasterization completely (0.00% CPU usage).
- Chart Scroll Protection: Automatically suppresses chart history sliding
  (CHART_MOUSE_SCROLL) during active HUD dragging and safely restores it on release.
- Two-Phase Hit-Testing: Interactive controls (buttons, sliders, toggles) receive
  first-priority click focus, cleanly separating widget actions from window drags.

### Subsystems & Components
- Core State & Input (Core/):
  * UInputState: Mouse/keyboard tracking, deltas, and chart scroll lock.
  * UState: Retained state hash map in pure MQL5 with 64-bit FNV-1a hashing.
  * UIdStack: Hierarchical identifier scoping preventing widget ID collisions.
  * ULayout: Automatic cursor placement supporting SameLine, Indent, and Unindent.
  * UEventQueue: Non-blocking circular UI event queue for decoupled handling.
  * UTheme: Institutional OneDark/Nord dark color palette and typography metrics.
- Rendering Backends (Render/):
  * URendererCanvas: Isolated per-hub surfaces with 32-bit ARGB alpha transparency.
  * URendererNative: Native MT5 object pool (OBJ_RECTANGLE_LABEL) with diff caching.
  * UFont: Anti-aliased font metrics and width cache.
- Complete Widget Suite (Widgets/):
  * UButton: Click-on-release standard, accent, and emergency panic buttons.
  * UToggle: Smooth draggable/clickable iOS-style toggle switches.
  * USlider: Draggable horizontal float and integer sliders.
  * UProgressBar: Adaptive progress bars with dynamic green->amber->red color ramps.
  * UHeader: Collapsible section headers with immediate-mode state retention.
  * ULabel & USeparator: Formatted text, colored metrics, and horizontal dividers.
- Window Management (Windows/):
  * UWindow: Window container with titlebar, collapse toggle, and coordinate clipping.
  * UWindowManager: Multi-window coordinator with GlobalVariable persistence across
    chart timeframe changes and backward-compatible key resolution.

### Tooling, Documentation & Reference Implementation
- Examples/EA_DearMQL5_Demo.mq5: Complete reference Prop-Firm cockpit HUD.
- README.md: Comprehensive institutional English documentation for GitHub and Algo Forge.
- Docs/ARCHITECTURE.md: Technical architecture specification with Mermaid lifecycle.
2026-10-12 08:35:18 -03:00

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MQL5

//+------------------------------------------------------------------+
//| UButton.mqh |
//| Copyright 2026, DearMQL5 GUI Engine |
//| https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2026, DearMQL5 GUI Engine"
#property link "https://www.mql5.com"
#property strict
#include "UWidget.mqh"
#include "..\Render\UFont.mqh"
/// Clickable button widget with hover, active feedback and auto-sizing.
class UButton
{
public:
/// Computes button dimensions based on label and padding.
static void GetBoundingBox(const string label, const int custom_w, const int custom_h,
int &out_w, int &out_h)
{
SUTheme th = UTheme::Get();
if(custom_w > 0)
out_w = custom_w;
else
out_w = UFont::MeasureTextWidth(label, th.font_size, th.font_name) + (th.padding_x * 2);
out_h = (custom_h > 0) ? custom_h : th.widget_height;
}
/// Resolves button background color based on interaction state.
static uint GetStateColor(const bool hovered, const bool active, const uint base_color = 0)
{
SUTheme th = UTheme::Get();
if(base_color != 0)
{
if(active) return(base_color);
if(hovered) return(base_color | 0x202020);
return(base_color);
}
if(active) return(th.button_active);
if(hovered) return(th.button_hover);
return(th.button_bg);
}
};