// Numbas version: exam_results_page_options {"name": "Use canvas to draw a rectangle", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"showfrontpage": false, "preventleave": false, "allowregen": true}, "question_groups": [{"questions": [{"variable_groups": [], "statement": "

This rectangle is {w} metres wide and {h} metres long.

\n

{rectangle(w,h)}

", "advice": "", "functions": {"rectangle": {"language": "javascript", "definition": "\n var c = document.createElement('canvas');\n \$(c).attr('width',w+40).attr('height',h+40);\n var context = c.getContext('2d');\n \n //fill in rectangle with a light shade\n context.fillStyle = '#eee';\n context.fillRect(5,5,w,h);\n \n //draw outline\n context.strokeStyle = '#000';\n context.lineWidth = 3;\n context.strokeRect(5,5,w,h);\n \n //draw labels\n context.fillStyle = '#000';\n context.font = '20px sans-serif';\n var wstring = w+'m';\n var tw = context.measureText(wstring).width;\n console.log(tw);\n context.fillText(wstring,5+(w-tw)/2,5+h+25);\n \n var hstring = h+'m';\n var hw = context.measureText(hstring).width;\n context.save();\n context.translate(5+w+25,5+(h+hw)/2);\n context.rotate(-Math.PI/2);\n context.fillText(hstring,0,0);\n \n return c;\n ", "type": "html", "parameters": [["w", "number"], ["h", "number"]]}}, "rulesets": {}, "tags": ["canvas", "demo", "function", "graphic"], "preamble": {"css": "", "js": ""}, "parts": [{"maxValue": "2(w+h)", "correctAnswerFraction": false, "minValue": "2(w+h)", "marks": 1, "showPrecisionHint": false, "prompt": "

What is the rectangle's perimeter, in metres?

", "allowFractions": false, "type": "numberentry", "showCorrectAnswer": true, "scripts": {}}, {"maxValue": "w*h", "correctAnswerFraction": false, "minValue": "w*h", "marks": 1, "showPrecisionHint": false, "prompt": "

What is the rectangle's area, in metres?

", "allowFractions": false, "type": "numberentry", "showCorrectAnswer": true, "scripts": {}}], "variablesTest": {"condition": "", "maxRuns": 100}, "variables": {"h": {"name": "h", "description": "", "templateType": "anything", "definition": "random(50..100#5)", "group": "Ungrouped variables"}, "w": {"name": "w", "description": "", "templateType": "anything", "definition": "random(100..200#5)", "group": "Ungrouped variables"}}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}], "showQuestionGroupNames": false, "ungrouped_variables": ["h", "w"], "name": "Use canvas to draw a rectangle", "type": "question", "metadata": {"description": "

The custom function `rectangle(width,height)` draws a rectangle with the given dimensions, along with some labels.

", "licence": "Creative Commons Attribution 4.0 International", "notes": "

Doesn't work in IE8, because it doesn't support the canvas element.

"}, "question_groups": [{"name": "", "pickQuestions": 0, "questions": [], "pickingStrategy": "all-ordered"}]}], "pickingStrategy": "all-ordered"}], "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}]}