Text is using wrong height metric when document is scaled

[akc42]

This is similar to #658 except in this case I am not rotating the document but scaling it. If I don't specify the height as an option to the doc.text call, it calculates it by using the page margins. However the page margins are in original units, whereas I am working in a scaled environment where my y values are (in my case) much larger that the points units being used for the page. As a result, as I get down the page but not actually to the bottom it thinks I am writing off the page and starts a new page.