Add `beginClip()` and `endClip()` masking functions

從 Core/Environment/Rendering 區域開始，閱讀現有的 mask() 行為以及連結的 p5.js beginClip() 參考。定義 beginClip()、endClip() 和可選的 invert 旗標應如何運作，然後驗證兩次呼叫之間的繪圖指令是否產生預期的正常和反向裁切行為。

Relevant sub-area for this feature?

Core/Environment/Rendering

Feature details

Feature description

Add beginClip() and endClip() to define clipping masks using drawing commands. Shapes drawn between these calls become the mask. An optional invert flag enables inverse masking.

Benefits

• More intuitive and less verbose than mask()
• Matches p5.js API and reduces cognitive load when switching from one to the other

Challenges

• Not sure

Additional context

See https://p5js.org/reference/p5/beginClip/

Example code

This mask() code...

  // Create pattern graphics
  pattern = createGraphics(width, height);
  pattern.beginDraw();
  pattern.background(255);
  pattern.stroke(0);
  pattern.strokeWeight(2);
  for (int x = 0; x < width; x += 10) {
    pattern.line(x, 0, x, height);
  }
  pattern.endDraw();

  // Create mask graphics (white circle on black)
  maskImg = createGraphics(width, height);
  maskImg.beginDraw();
  maskImg.background(0);
  maskImg.noStroke();
  maskImg.fill(255);
  maskImg.ellipse(width/2, height/2, 200, 200);
  maskImg.endDraw();

  // Apply mask to pattern
  pattern.mask(maskImg);

... becomes this using beginClip()/endClip():

  // Define clipping region
  beginClip();
  ellipse(width/2, height/2, 200, 200);
  endClip();

  // Draw pattern inside the clip
  stroke(0);
  strokeWeight(2);
  for (int x = 0; x < width; x += 10) {
    line(x, 0, x, height);
  }

Would you like to help implement this feature?

No, I’m just suggesting the feature